Casper source code is quite heavily documented using jsdoc, but below you'll find the whole API documentation with sample code.

The Casper class

The most easy way to instantiate a casper instance is to use the module's create() method:

var casper = require('casper').create();

But you can also retrieve the main Function and instantiate it by yourself:

var casper = new require('casper').Casper();

Hint Also, check out how to extend Casper with your own methods.

Casper([Object options])

Both the Casper constructor and the create() function accept a single options argument which is a standard javascript object:

var casper = require('casper').create({
    verbose: true,
    logLevel: "debug"
});

Casper options

All the available options are detailed below:

Name	Type	Default	Description
clientScripts	Array	[]	A collection of script filepaths to include to every page loaded
exitOnError	Boolean	true	Sets if CasperJS must exit when an uncaught error has been thrown by the script.
httpStatusHandlers	Object	{}	A javascript Object containing functions to call when a requested resource has a given HTTP status code. A dedicated sample is provided as an example.
logLevel	String	"error"	Logging level (see the logging section for more information)
onAlert	Function	null	A function to be called when a javascript alert() is triggered
onDie	Function	null	A function to be called when Casper#die() is called
onError	Function	null	A function to be called when an "error" level event occurs
onLoadError	Function	null	A function to be called when a requested resource cannot be loaded
onPageInitialized	Function	null	A function to be called after WebPage instance has been initialized
onResourceReceived	Function	null	Proxy method for PhantomJS' WebPage#onResourceReceived() callback, but the current Casper instance is passed as first argument.
onResourceRequested	Function	null	Proxy method for PhantomJS' WebPage#onResourceRequested() callback, but the current Casper instance is passed as first argument.
onStepComplete	Function	null	A function to be executed when a step function execution is finished.
onStepTimeout	Function	Function	A function to be executed when a step function execution time exceeds the value of the stepTimeout option, if any has been set. By default, on timeout the script will exit displaying an error, except in test environment where it will just add a failure to the suite results.
onTimeout	Function	Function	A function to be executed when script execution time exceeds the value of the timeout option, if any has been set. By default, on timeout the script will exit displaying an error, except in test environment where it will just add a failure to the suite results.
onWaitTimeout	Function	Function	A function to be executed when a waitFor function execution time exceeds the value of the waitTimeout option, if any has been set. By default, on timeout the script will exit displaying an error, except in test environment where it will just add a failure to the suite results.
page	WebPage	null	An existing WebPage instance
pageSettings	Object	{}	PhantomJS's WebPage settings object. Available settings are: javascriptEnabled defines whether to execute the script in the page or not (default to true) loadImages defines whether to load the inlined images or not loadPlugins defines whether to load NPAPI plugins (Flash, Silverlight, ...) or not localToRemoteUrlAccessEnabled defines whether local resource (e.g. from file) can access remote URLs or not (default to false) userAgent defines the user agent sent to server when the web page requests resources. userName sets the user name used for HTTP authentication password sets the password used for HTTP authentication XSSAuditingEnabled defines whether load requests should be monitored for cross-site scripting attempts (default to false)
remoteScripts	Array	[]	Added in 1.0 A collection of remote script urls to include to every page loaded
safeLogs	Boolean	true	Added in 1.0 When this option is set to true — which is the default, any password information entered in <input type="password"> will be obfuscated in log messages. Set safeLogs to false to disclose passwords in plain text (not recommended).
stepTimeout	Number	null	Max step timeout in milliseconds; when set, every defined step function will have to execute before this timeout value has been reached. You can define the onStepTimeout() callback to catch such a case. By default, the script will die() with an error message.
timeout	Number	null	Max timeout in milliseconds
verbose	Boolean	false	Realtime output of log messages
viewportSize	Object	null	Viewport size, eg. {width: 800, height: 600}
waitTimeout	Number	5000	Default wait timeout, for wait family functions.

Example:

var casper = require('casper').create({
    clientScripts:  [
        'includes/jquery.js',      // These two scripts will be injected in remote
        'includes/underscore.js'   // DOM on every request
    ],
    logLevel: "info",              // Only "info" level messages will be logged
    onError: function(self, m) {   // Any "error" level message will be written
        console.log('FATAL:' + m); // on the console output and PhantomJS will
        self.exit();               // terminate
    },
    pageSettings: {
        loadImages:  false,        // The WebPage instance used by Casper will
        loadPlugins: false         // use these settings
    }
});

But no worry, usually you'll just need to instantiate Casper using require('casper').create().

Casper#back()

Moves back a step in browser's history.

casper.start('http://foo.bar/1')
casper.thenOpen('http://foo.bar/2');
casper.thenOpen('http://foo.bar/3');
casper.back();
casper.run(function() {
    console.log(this.getCurrentUrl()); // 'http://foo.bar/2'
});

Also have a look at Casper.forward().

Casper#base64encode(String url [, String method, Object data])

Encodes a resource using the base64 algorithm synchronously using client-side XMLHttpRequest.

Note We cannot use window.btoa() because it fails miserably in the version of WebKit shipping with PhantomJS.

Example: retrieving google logo image encoded in base64:

var base64logo = null;
casper.start('http://www.google.fr/', function() {
    base64logo = this.base64encode('http://www.google.fr/images/srpr/logo3w.png');
});

casper.run(function() {
    this.echo(base64logo).exit();
});

You can also perform an HTTP POST request to retrieve the contents to encode:

var base46contents = null;
casper.start('http://domain.tld/download.html', function() {
    base46contents = this.base64encode('http://domain.tld/', 'POST', {
        param1: 'foo',
        param2: 'bar'
    });
});

casper.run(function() {
    this.echo(base46contents).exit();
});

Casper#click(String selector)

Performs a click on the element matching the provided selector expression. The method tries two strategies sequentially:

1. trying to trigger a MouseEvent in Javascript
2. using native QtWebKit event if the previous attempt failed

Example:

casper.start('http://google.fr/');

casper.thenEvaluate(function(term) {
    document.querySelector('input[name="q"]').setAttribute('value', term);
    document.querySelector('form[name="f"]').submit();
}, 'CasperJS');

casper.then(function() {
    // Click on 1st result link
    this.click('h3.r a');
});

casper.then(function() {
    console.log('clicked ok, new location is ' + this.getCurrentUrl());
});

casper.run();

Casper#clickLabel(String label[, String tag])

Added in 0.6.10 Clicks on the first DOM element found containing label text. Optionaly ensures that the element node name is tag.

// <a href="...">My link is beautiful</a>
casper.then(function() {
    this.clickLabel('My link is beautiful', 'a');
});

// <button type="submit">But my button is sexier</button>
casper.then(function() {
    this.clickLabel('But my button is sexier', 'button');
});

Casper#capture(String targetFilepath, Object clipRect)

Proxy method for PhantomJS' WebPage#render. Adds a clipRect parameter for automatically setting page clipRect setting values and sets it back once done.

Example:

casper.start('http://www.google.fr/', function() {
    this.capture('google.png', {
        top: 100,
        left: 100,
        width: 500,
        height: 400
    });
});

casper.run();

Casper#captureBase64(String format[, Mixed area])

Added in 0.6.5 Computes the Base64 representation of a binary image capture of the current page, or an area within the page, in a given format.

Supported image formats are bmp, jpg, jpeg, png, ppm, tiff, xbm and xpm.

The area argument can be either of the following types:

• String: area is a CSS3 selector string, eg. div#plop form[name="form"] input[type="submit"]
• clipRect: area is a clipRect object, eg. {"top":0,"left":0,"width":320,"height":200}

• Object: area is a selector object, eg. an XPath selector

• Example:*

casper.start('http://google.com', function() {
    // selector capture
    console.log(this.captureBase64('png', '#lga'));
    // clipRect capture
    console.log(this.captureBase64('png', {
        top: 0,
        left: 0,
        width: 320,
        height: 200
    }));
    // whole page capture
    console.log(this.captureBase64('png'));
});

casper.run();

Casper#captureSelector(String targetFile, String selector)

Captures the page area containing the provided selector.

Example:

casper.start('http://www.weather.com/', function() {
    this.captureSelector('weather.png', '#wx-main');
});

casper.run();

Casper#clear()

Added in 0.6.5 Clears the current page execution environment context. Useful to avoid having previously loaded DOM contents being still active.

Think of it as a way to stop javascript execution within the remote DOM environment.

Example:

casper.start('http://www.google.fr/', function() {
    this.clear(); // javascript execution in this page has been stopped
});

casper.then(function() {
    // ...
});

casper.run();

Casper#debugHTML([String selector, Boolean outer])

Outputs the results of getHTML() directly to the console. It takes the same arguments as getHTML().

Casper#debugPage()

Logs the textual contents of the current page directly to the standard output, for debugging purpose.

Example:

casper.start('http://www.google.fr/', function() {
    this.debugPage();
});

casper.run();

Casper#die(String message[, int status])

Exits phantom with a logged error message and an optional exit status code.

Example:

casper.start('http://www.google.fr/', function() {
    this.die("Fail.", 1);
});

casper.run();

Casper#download(String url, String target[, String method, Object data])

Saves a remote resource onto the filesystem. You can optionally set the HTTP method using the method argument, and pass request arguments through the data object (see base64encode).

casper.start('http://www.google.fr/', function() {
    var url = 'http://www.google.fr/intl/fr/about/corporate/company/';
    this.download(url, 'google_company.html');
});

casper.run(function() {
    this.echo('Done.').exit();
});

Casper#each(Array array, Function fn)

Iterates over provided array items and execute a callback.

Example:

var links = [
    'http://google.com/',
    'http://yahoo.com/',
    'http://bing.com/'
];

casper.start().each(links, function(self, link) {
    self.thenOpen(link, function() {
        this.echo(this.getTitle());
    });
});

casper.run();

Hint Have a look at the googlematch.js sample script for a concrete use case.

Casper#echo(String message[, String style])

Prints something to stdout, optionally with some fancy color (see the Colorizer section of this document for more information).

Example:

casper.start('http://www.google.fr/', function() {
    this.echo('Page title is: ' + this.evaluate(function() {
        return document.title;
    }), 'INFO'); // Will be printed in green on the console
});

casper.run();

Casper#evaluate(Function fn[, arg1[, arg2[, …]])

Basically PhantomJS' WebPage#evaluate equivalent. Evaluates an expression in the current page DOM context.

Example:

casper.evaluate(function(username, password) {
    document.querySelector('#username').value = username;
    document.querySelector('#password').value = password;
    document.querySelector('#submit').click();
}, 'sheldon.cooper', 'b4z1ng4');

Warning The pre-1.0 way of passing arguments using an object has been kept for BC purpose, though it may not work in some case; so you're encouraged to use the method described above.

Note For filling and submitting forms, rather use the Casper#fill() method.

Note The concept behind this method is probably the most difficult to understand when discovering CasperJS. As a reminder, think of the evaluate() method as a gate between the CasperJS environment and the one of the page you have opened; everytime you pass a closure to evaluate(), you're entering the page and execute code as if you were using the browser console.

Here's a quickly drafted diagram trying to basically explain the separation of concerns:

Casper#evaluateOrDie(Function fn[, String message])

Evaluates an expression within the current page DOM and die() if it returns anything but true.

Example:

casper.start('http://foo.bar/home', function() {
    this.evaluateOrDie(function() {
        return /logged in/.match(document.title);
    }, 'not authenticated');
});

casper.run();

Casper#exit([int status])

Exits PhantomJS with an optional exit status code.

Casper#exists(String selector)

Checks if any element within remote DOM matches the provided selector.

casper.start('http://foo.bar/home', function() {
    if (this.exists('#my_super_id')) {
        this.echo('found #my_super_id', 'INFO');
    } else {
        this.echo('#my_super_id not found', 'ERROR');
    }
});

casper.run();

Casper#fetchText(String selector)

Retrieves text contents matching a given selector expression. If you provide one matching more than one element, their textual contents will be concatenated.

casper.start('http://google.com/search?q=foo', function() {
    this.echo(this.fetchText('h3'));
}).run();

Casper#forward()

Moves a step forward in browser's history.

casper.start('http://foo.bar/1')
casper.thenOpen('http://foo.bar/2');
casper.thenOpen('http://foo.bar/3');
casper.back();    // http://foo.bar/2
casper.back();    // http://foo.bar/1
casper.forward(); // http://foo.bar/2
casper.run();

Also have a look at Casper.back().

Casper#log(String message[, String level, String space])

Logs a message with an optional level in an optional space. Available levels are debug, info, warning and error. A space is a kind of namespace you can set for filtering your logs. By default, Casper logs messages in two distinct spaces: phantom and remote, to distinguish what happens in the PhantomJS environment from the remote one.

Example:

casper.start('http://www.google.fr/', function() {
    this.log("I'm logging an error", "error");
});

casper.run();

Casper#fill(String selector, Object values[, Boolean submit])

Fills the fields of a form with given values and optionally submits it.

Example with this sample html form:

<form action="/contact" id="contact-form" enctype="multipart/form-data">
    <input type="text" name="subject"/>
    <textearea name="content"></textearea>
    <input type="radio" name="civility" value="Mr"/> Mr
    <input type="radio" name="civility" value="Mrs"/> Mrs
    <input type="text" name="name"/>
    <input type="email" name="email"/>
    <input type="file" name="attachment"/>
    <input type="checkbox" name="cc"/> Receive a copy
    <input type="submit"/>
</form>

A script to fill and submit this form:

casper.start('http://some.tld/contact.form', function() {
    this.fill('form#contact-form', {
        'subject':    'I am watching you',
        'content':    'So be careful.',
        'civility':   'Mr',
        'name':       'Chuck Norris',
        'email':      'chuck@norris.com',
        'cc':         true,
        'attachment': '/Users/chuck/roundhousekick.doc'
    }, true);
});

casper.then(function() {
    this.evaluateOrDie(function() {
        return /message sent/.test(document.body.innerText);
    }, 'sending message failed');
});

casper.run(function() {
    this.echo('message sent').exit();
});

Please Don't use CasperJS nor PhantomJS to send spam, or I'll be calling the Chuck. More seriously, please just don't.

Warning The fill() method currently can't fill file fields using XPath selectors; PhantomJS natively only allows the use of CSS3 selectors in its uploadFile method, hence this limitation.

Casper#getCurrentUrl()

Retrieves current page URL. Note the url will be url-decoded.

Example:

casper.start('http://www.google.fr/', function() {
    this.echo(this.getCurrentUrl()); // "http://www.google.fr/"
});

casper.run();

Casper#getElementAttribute(String selector, String attribute)

Added in 1.0 Retrieves the value of an attribute on the first element matching the provided selector.

Example:

var casper = require('casper').create();

casper.start('http://www.google.fr/', function() {
    require('utils').dump(this.getElementAttribute('div[title="Google"]', 'title')); // "Google"
});

casper.run();

Casper#getElementBounds(String selector)

Retrieves boundaries for a DOM element matching the provided selector.

It returns an Object with four keys: top, left, width and height, or null if the selector doesn't exist.

Example:

var casper = require('casper').create();

casper.start('http://www.google.fr/', function() {
    require('utils').dump(this.getElementBounds('div[title="Google"]'));
});

casper.run();

This will output something like:

{
    "height": 95,
    "left": 352,
    "top": 16,
    "width": 275
}

Casper#getElementsBounds(String selector)

Added in 1.0.0 Retrieves a list of boundaries for all DOM elements matching the provided selector.

It returns an array of objects with four keys: top, left, width and height (see casper.getElementBounds()).

Casper#getElementInfo(String selector)

Retrieves information about the first element matching the provided selector.

Added in 1.0

casper.start('http://google.com/', function() {
    require('utils').dump(this.getElementInfo('#hplogo'));
});

Gives something like:

{
    "nodeName": "div",
    "attributes": {
        "dir": "ltr",
        "title": "Google",
        "align": "left",
        "id": "hplogo",
        "onload": "window.lol&&lol()",
        "style": "background:url(images/srpr/logo3w.png) no-repeat;background-size:275px 95px;height:95px;width:275px"
    },
    "tag": "<div dir=\"ltr\" title=\"Google\" align=\"left\" id=\"hplogo\" onload=\"window.lol&amp;&amp;lol()\" style=\"background:url(images/srpr/logo3w.png) no-repeat;background-size:275px 95px;height:95px;width:275px\"><div nowrap=\"nowrap\" style=\"color:#777;font-size:16px;font-weight:bold;position:relative;left:214px;top:70px\">France</div></div>",
    "html": "<div nowrap=\"nowrap\" style=\"color:#777;font-size:16px;font-weight:bold;position:relative;left:214px;top:70px\">France</div>",
    "text": "France\n",
    "x": 582.5,
    "y": 192,
    "width": 275,
    "height": 95,
    "visible": true
}

Casper#getFormValues(String selector)

Added in 1.0 Retrieves a given form all of its field values.

Example:

casper.start('http://www.google.fr/', function() {
    this.fill('form', {q: 'plop'}, false);
    this.echo(this.getFormValues('form').q); // 'plop'
});

casper.run();

Casper#getGlobal(String name)

Retrieves a global variable value within the remote DOM environment by its name. Basically, getGlobal('foo') will retrieve the value of window.foo from the page.

Example:

casper.start('http://www.google.fr/', function() {
    this.echo(this.getGlobal('innerWidth')); // 1024
});

casper.run();

Casper#getHTML([String selector, Boolean outer])

Added in 1.0 Retrieves HTML code from the current page. By default, it outputs the whole page HTML contents:

casper.start('http://www.google.fr/', function() {
    this.echo(this.getHTML());
});

casper.run();

getHTML() can also dump HTML contents matching a given CSS3/XPath selector:

<html>
  <body>
    <h1 id="foobar">Plop</h1>
  </body>
</html>

casper.start('http://www.site.tld/', function() {
    this.echo(this.getHTML('h1#foobar')); // => 'Plop'
});

The outer argument allows to retrieve the outer HTML contents of the matching element:

casper.start('http://www.site.tld/', function() {
    this.echo(this.getHTML('h1#foobar', true)); // => '<h1 id="foobar">Plop</h1>'
});

Casper#getPageContent()

Added in 1.0.0 Retrieves current page contents, dealing with exotic other content types than HTML.

Example:

var casper = require('casper').create();

casper.start().then(function() {
    this.open('http://search.twitter.com/search.json?q=casperjs', {
        method: 'get',
        headers: {
            'Accept': 'application/json'
        }
    });
});

casper.run(function() {
    require('utils').dump(JSON.parse(this.getPageContent()));
    this.exit();
});

Casper#getTitle()

Retrieves current page title.

Example:

casper.start('http://www.google.fr/', function() {
    this.echo(this.getTitle()); // "Google"
});

casper.run();

Casper#mouseEvent(String type, String selector)

Added in 0.6.9 Triggers a mouse event on the first element found matching the provided selector.

Supported events are mouseup, mousedown, click, mousemove, mouseover and mouseout.

Example:

casper.start('http://www.google.fr/', function() {
    this.mouseEvent('click', 'h2 a');
});

casper.run();

Casper#open(String location, Object Settings)

Performs an HTTP request for opening a given location. You can forge GET, POST, PUT, DELETE and HEAD requests.

Example for a standard GET request:

casper.start();

casper.open('http://www.google.com/').then(function() {
    this.echo('GOT it.');
});

casper.run();

Example for a POST request:

casper.start();

casper.open('http://some.testserver.com/post.php', {
    method: 'post',
    data:   {
        'title': 'Plop',
        'body':  'Wow.'
    }
});

casper.then(function() {
    this.echo('POSTED it.');
});

casper.run();

To pass nested parameters arrays:

casper.open('http://some.testserver.com/post.php', {
       method: 'post',
       data: {
            'standard_param': 'foo',
            'nested_param[]': [       // please note the use of square brackets!
                'Something',
                'Something else'
            ]
       }
});

Added in 1.0 You can also set custom request headers to send when performing an outgoing request, passing the headers option:

casper.open('http://some.testserver.com/post.php', {
    method: 'post',
    data:   {
        'title': 'Plop',
        'body':  'Wow.'
    },
    headers: {
        'Accept-Language': 'fr,fr-fr;q=0.8,en-us;q=0.5,en;q=0.3'
    }
});

Casper#reload([Function then])

Added in 1.0 Reloads current page location.

Example:

casper.start('http://google.com', function() {
    this.echo("loaded");
    this.reload(function() {
        this.echo("loaded again");
    });
});

casper.run();

Casper#repeat(int times, function then)

Repeats a navigation step a given number of times.

Example:

casper.start().repeat(3, function() {
    this.echo("Badger");
});

casper.run();

Casper#resourceExists(Mixed test)

Checks if a resource has been loaded. You can pass either a function or a string to perform the test.

Example:

casper.start('http://www.google.com/', function() {
    if (this.resourceExists('logo3w.png')) {
        this.echo('Google logo loaded');
    } else {
        this.echo('Google logo not loaded', 'ERROR');
    }
});

casper.run();

Note If you want to wait for a resource to be loaded, use the waitForResource() method.

Casper#run(fn onComplete[, int time])

Runs the whole suite of steps and optionally executes a callback when they've all been done. Obviously, calling this method is mandatory in order to run the Casper navigation suite.

Casper suite won't run:

casper.start('http://foo.bar/home', function() {
    // ...
});

// hey, it's missing .run() here!

Casper suite will run:

casper.start('http://foo.bar/home', function() {
    // ...
});

casper.run();

Casper.run() also accepts an onComplete callback, which you can consider as a custom final step to perform when all the other steps have been executed. Just don't forget to exit() Casper if you define one!

casper.start('http://foo.bar/home', function() {
    // ...
});

casper.then(function() {
    // ...
});

casper.run(function() {
    this.echo('So the whole suite ended.');
    this.exit(); // <--- don't forget me!
});

Casper#sendKeys(Selector selector, String keys[, Object options])

Added in 1.0 Sends native keyboard events to the element matching the provided selector:

casper.then(function() {
    this.sendKeys('form.contact input#name', 'Duke');
    this.sendKeys('form.contact textarea#message', "Damn, I'm looking good.");
    this.click('form.contact input[type="submit"]');
});

Casper#setHttpAuth(String username, String password)

Sets HTTP_AUTH_USER and HTTP_AUTH_PW values for HTTP based authentication systems.

Example:

casper.start();

casper.setHttpAuth('sheldon.cooper', 'b4z1ng4');

casper.thenOpen('http://password-protected.domain.tld/', function() {
    this.echo("I'm in. Bazinga.");
})
casper.run();

Of course you can directly pass the auth string in the url to open:

var url = 'http://sheldon.cooper:b4z1ng4@password-protected.domain.tld/';

casper.start(url, function() {
    this.echo("I'm in. Bazinga.");
})

casper.run();

Casper#start(String url[, function then])

Configures and starts Casper, then open the provided url and optionally adds the step provided by the then argument.

Example:

casper.start('http://google.fr/', function() {
    this.echo("I'm loaded.");
});

casper.run();

Alternatively:

casper.start('http://google.fr/');

casper.then(function() {
    this.echo("I'm loaded.");
});

casper.run();

Or alternatively:

casper.start('http://google.fr/');

casper.then(function() {
    casper.echo("I'm loaded.");
});

casper.run();

Or even:

casper.start('http://google.fr/');

casper.then(function(self) {
    self.echo("I'm loaded.");
});

casper.run();

Matter of taste!

Note You must call the start() method in order to be able to add navigation steps and run the suite. If you don't you'll get an error message inviting you to do so anyway.

Casper#status(Boolean asString)

Added in 1.0 Returns the status of current Casper instance.

Example:

casper.start('http://google.fr/', function() {
    this.echo(this.status(true));
});

casper.run();

Casper#then(Function fn)

This method is the standard way to add a new navigation step to the stack, by providing a simple function:

casper.start('http://google.fr/');

casper.then(function() {
    this.echo("I'm in your google.");
});

casper.then(function() {
    this.echo('Now, let me write something');
});

casper.then(function() {
    this.echo('Oh well.');
});

casper.run();

You can add as many steps as you need. Note that the current Casper instance automatically binds the this keyword for you within step functions.

To run all the steps you defined, call the run() method, and voila.

Note You must start() the casper instance in order to use the then() method.

Accessing the current HTTP response

Added in 1.0 You can access the current HTTP response object using the first parameter of your step callback:

casper.start('http://www.google.fr/', function(response) {
    require('utils').dump(response);
});

That gives:

$ casperjs dump-headers.js
{
    "contentType": "text/html; charset=UTF-8",
    "headers": [
        {
            "name": "Date",
            "value": "Thu, 18 Oct 2012 08:17:29 GMT"
        },
        {
            "name": "Expires",
            "value": "-1"
        },
        // ... lots of other headers
    ],
    "id": 1,
    "redirectURL": null,
    "stage": "end",
    "status": 200,
    "statusText": "OK",
    "time": "2012-10-18T08:17:37.068Z",
    "url": "http://www.google.fr/"
}

So to fetch a particular header by its name:

casper.start('http://www.google.fr/', function(response) {
    this.echo(response.headers.get('Date'));
});

That gives:

$ casperjs dump-headers.js
Thu, 18 Oct 2012 08:26:34 GMT

Casper#thenClick(String selector)

Adds a new navigation step to click a given selector and add a new navigation step in a single operation.

Example:

// Querying for "Chuck Norris" on Google
casper.start('http://casperjs.org/').thenClick('a', function() {
    this.echo("I clicked on first link found, the page is now loaded.");
});

casper.run();

This method is basically a convenient a shortcut for chaining a then() and an evaluate() calls.

Casper#thenEvaluate(Function fn[, arg1[, arg2[, …]])

Adds a new navigation step to perform code evaluation within the current retrieved page DOM.

Example:

// Querying for "Chuck Norris" on Google
casper.start('http://google.fr/').thenEvaluate(function(term) {
    document.querySelector('input[name="q"]').setAttribute('value', term);
    document.querySelector('form[name="f"]').submit();
}, 'Chuck Norris');

casper.run();

This method is basically a convenient a shortcut for chaining a then() and an evaluate() calls.

Casper#thenOpen(String location[, mixed options])

Adds a new navigation step for opening a new location, and optionally add a next step when its loaded.

Example:

casper.start('http://google.fr/').then(function() {
    this.echo("I'm in your google.");
});

casper.thenOpen('http://yahoo.fr/', function() {
    this.echo("Now I'm in your yahoo.")
});

casper.run();

Added in 1.0 You can also specify request settings by passing a setting object as the second argument:

casper.start().thenOpen('http://url.to/some/uri', {
    method: "post",
    data: {
      username: 'chuck',
      password: 'n0rr15'
    }
}, function() {
    this.echo("POST request has been sent.")
});

casper.run();

Casper#thenOpenAndEvaluate(String location[, function then[, arg1[, arg2[, …]])

Basically a shortcut for opening an url and evaluate code against remote DOM environment.

Example:

casper.start('http://google.fr/').then(function() {
    this.echo("I'm in your google.");
});

casper.thenOpenAndEvaluate('http://yahoo.fr/', function() {
    var f = document.querySelector('form');
    f.querySelector('input[name=q]').value = 'chuck norris';
    f.submit();
});

casper.run(function() {
    this.debugPage();
    this.exit();
});

Casper#toString()

Added in 1.0 Returns a string representation of current Casper instance.

Example:

casper.start('http://google.fr/', function() {
    this.echo(this); // [object Casper], currently at http://google.fr/
});

casper.run();

Casper#userAgent(String agent)

Added in 1.0 Sets the User-Agent string to send through headers when performing requests.

Example:

casper.start();

casper.userAgent('Mozilla/5.0 (Macintosh; Intel Mac OS X)');

casper.thenOpen('http://google.com/', function() {
    this.echo("I'm a Mac.");
});

casper.userAgent('Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)');

casper.thenOpen('http://google.com/', function() {
    this.echo("I'm a PC.");
});

casper.run();

Casper#viewport(Number width, Number height)

Changes current viewport size.

Example:

casper.viewport(1024, 768);

Note PhantomJS comes with a default viewport size of 400x300, and CasperJS doesn't override it by default.

Casper#visible(String selector)

Checks if the DOM element matching the provided selector expression is visible in remote page.

Example:

casper.start('http://google.com/', function() {
    if (this.visible('#hplogo')) {
        this.echo("I can see the logo");
    } else {
        this.echo("I can't see the logo");
    }
});

Casper#wait(Number timeout[, Function then])

Pause steps suite execution for a given amount of time, and optionally execute a step on done.

Example:

casper.start('http://yoursite.tld/', function() {
    this.wait(1000, function() {
        this.echo("I've waited for a second.");
    });
});

casper.run();

You can also write the same thing like this:

casper.start('http://yoursite.tld/');

casper.wait(1000, function() {
    this.echo("I've waited for a second.");
});

casper.run();

Casper#waitFor(Function testFx[, Function then, Function onTimeout, Number timeout])

Waits until a function returns true to process any next step.

You can also set a callback on timeout using the onTimeout argument, and set the timeout using the timeout one, in milliseconds. The default timeout is set to 5000ms.

Example:

casper.start('http://yoursite.tld/');

casper.waitFor(function check() {
    return this.evaluate(function() {
        return document.querySelectorAll('ul.your-list li').length > 2;
    });
}, function then() {
    this.captureSelector('yoursitelist.png', 'ul.your-list');
});

casper.run();

Example using the onTimeout callback:

casper.start('http://yoursite.tld/');

casper.waitFor(function check() {
    return this.evaluate(function() {
        return document.querySelectorAll('ul.your-list li').length > 2;
    });
}, function then() {    // step to execute when check() is ok
    this.captureSelector('yoursitelist.png', 'ul.your-list');
}, function timeout() { // step to execute if check has failed
    this.echo("I can't haz my screenshot.").exit();
});

casper.run();

Casper#waitForPopup(String|RegExp urlPattern[, Function then, Function onTimeout, Number timeout])

Added in 1.0 Waits for a popup having its url matching the provided pattern to be opened and loaded.

The currently loaded popups are available in the Casper.popups array-like property.

casper.start('http://foo.bar/').then(function() {
    this.test.assertTitle('Main page title');
    this.clickLabel('Open me a popup');
});

// this will wait for the popup to be opened and loaded
casper.waitForPopup(/popup\.html$/, function() {
    this.test.assertEquals(this.popups.length, 1);
});

// this will set the popup DOM as the main active one only for time the
// step closure being executed
casper.withPopup(/popup\.html$/, function() {
    this.test.assertTitle('Popup title');
});

// next step will automatically revert the current page to the initial one
casper.then(function() {
    this.test.assertTitle('Main page title');
});

Casper#waitForSelector(String selector[, Function then, Function onTimeout, Number timeout])

Waits until an element matching the provided selector expression exists in remote DOM to process any next step. Uses Casper.waitFor().

Example:

casper.start('https://twitter.com/#!/n1k0');

casper.waitForSelector('.tweet-row', function() {
    this.captureSelector('twitter.png', 'html');
});

casper.run();

Casper#waitWhileSelector(String selector[, Function then, Function onTimeout, Number timeout])

Waits until an element matching the provided selector expression does not exist in remote DOM to process a next step. Uses Casper.waitFor().

Example:

casper.start('http://foo.bar/');

casper.waitWhileSelector('.selector', function() {
    this.echo('.selector is no more!');
});

casper.run();

Casper#waitForResource(Function testFx[, Function then, Function onTimeout, Number timeout])

Wait until a resource that matches the given testFx is loaded to process a next step. Uses Casper.waitFor().

Example:

casper.start('http://foo.bar/', function() {
    this.waitForResource("foobar.png");
});

casper.then(function() {
    this.echo('foobar.png has been loaded.');
});

casper.run();

Another way to write the exact same behavior:

casper.start('http://foo.bar/');

casper.waitForResource("foobar.png", function() {
    this.echo('foobar.png has been loaded.');
});

casper.run();

Casper#waitForText(String|RegExp pattern[, Function then, Function onTimeout, Number timeout])

Added in 1.0 Waits until the passed text is present in the page contents before processing the immediate next step. Uses Casper.waitFor().

Added in 1.0.2 Added support for RegExp.

Example:

casper.start('http://why.univer.se/').waitForText("42", function() {
    this.echo('Found the answer.');
});

// new in 1.0.2
casper.thenOpen('http://why.univer.se/foo.html').waitForText(/\d+/, function() {
    this.echo('Found an answer.');
});

casper.run();

Casper#waitUntilVisible(String selector[, Function then, Function onTimeout, Number timeout])

Waits until an element matching the provided selector expression is visible in the remote DOM to process a next step. Uses Casper.waitFor().

Casper#waitWhileVisible(String selector[, Function then, Function onTimeout, Number timeout])

Waits until an element matching the provided selector expression is no longer visible in remote DOM to process a next step. Uses Casper.waitFor().

Casper#warn(String message)

Logs and prints a warning message to the standard output.

casper.warn("I'm a warning message.");

Casper#withFrame(String|Number frameInfo, Function then)

Added in 1.0 Switches the main page to the frame having the name or frame index number matching the passed argument, and processes a step. The page context switch only lasts until the step execution is finished:

casper.start('tests/site/frames.html', function() {
    this.test.assertTitle('FRAMESET TITLE');
});

casper.withFrame('frame1', function() {
    this.test.assertTitle('FRAME TITLE');
});

casper.withFrame(0, function() {
    this.test.assertTitle('FRAME TITLE');
});

casper.then(function() {
    this.test.assertTitle('FRAMESET TITLE');
});

Casper#withPopup(Mixed popupInfo, Function step)

Added in 1.0 Switches the main page to a popup matching the information passed as argument, and processes a step. The page context switch only lasts until the step execution is finished:

casper.start('http://foo.bar/').then(function() {
    this.test.assertTitle('Main page title');
    this.clickLabel('Open me a popup');
});

// this will wait for the popup to be opened and loaded
casper.waitForPopup(/popup\.html$/, function() {
    this.test.assertEquals(this.popups.length, 1);
});

// this will set the popup DOM as the main active one only for time the
// step closure being executed
casper.withPopup(/popup\.html$/, function() {
    this.test.assertTitle('Popup title');
});

// next step will automatically revert the current page to the initial one
casper.then(function() {
    this.test.assertTitle('Main page title');
});

Note: The currently loaded popups are available in the Casper.popups array-like property.

Casper#zoom(Number factor)

Added in 1.0 Sets the current page zoom factor.

var casper = require('casper').create();

casper.start().zoom(2).thenOpen('http://google.com', function() {
    this.capture('big-google.png');
});

casper.run();