dompurify
Advanced tools
Package description
DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML, and SVG. It helps prevent Cross-Site Scripting (XSS) attacks by sanitizing HTML content to ensure it's safe to insert into the DOM. It is written in JavaScript and works in all modern web browsers.
Sanitizing HTML strings
This feature allows you to sanitize HTML strings to prevent XSS attacks. The code sample demonstrates how to sanitize a string that contains a potentially malicious script. The result of this code would be a safe string with the malicious parts removed.
DOMPurify.sanitize('<img src=x onerror=alert(1)//>');Configuring the sanitizer
DOMPurify can be configured to allow certain tags, attributes, or schemes. In the code sample, the sanitizer is configured to allow only 'img' tags and will strip out any other tags, including scripts or event handlers.
DOMPurify.sanitize('<img src=x onerror=alert(1)//>', {ALLOWED_TAGS: ['img']});Hooking into sanitization
DOMPurify allows you to add hooks that can modify the content during the sanitization process. In the code sample, a hook is added that will be called after the attributes of all nodes have been sanitized, allowing for custom manipulation of the nodes.
DOMPurify.addHook('afterSanitizeAttributes', function(node) { /* manipulate node */ });sanitize-html is another HTML sanitizer that can clean up user-generated HTML, preventing XSS attacks. It is similar to DOMPurify but has a different API and set of defaults. It also allows for a high degree of customization in terms of what tags and attributes are allowed.
xss is a package that aims to filter input from users to prevent XSS attacks. It is similar to DOMPurify but includes different options and is more focused on filtering input as opposed to sanitizing existing HTML content.
js-xss is a whitelist-based HTML sanitizer. Like DOMPurify, it can prevent XSS attacks by sanitizing HTML content. It provides a different API and allows for customization of the whitelist to control which tags and attributes are considered safe.
Readme
DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. It's written in JavaScript and works in all modern browsers (Safari, Opera (15+), Internet Explorer (10+), Firefox and Chrome - as well as almost anything else using Blink or WebKit). It doesn't break on IE6 or other legacy browsers. It simply does nothing there.
DOMPurify is written by security people who have vast background in web attacks and XSS. Fear not. For more details please also read about our Security Goals & Threat Model
DOMPurify sanitizes HTML and prevents XSS attacks. You can feed DOMPurify with string full of dirty HTML and it will return a string with clean HTML. DOMPurify will strip out everything that contains dangerous HTML and thereby prevent XSS attacks and other nastiness. It's also damn bloody fast. We use the technologies the browser provides and turn them into an XSS filter. The faster your browser, the faster DOMPurify will be.
It's easy. Just include DOMPurify on your website.
<script type="text/javascript" src="purify.js"></script>
Afterwards you can sanitize strings by executing the following code:
var clean = DOMPurify.sanitize(dirty);
If you're using an AMD module loader like Require.js, you can load this script asynchronously as well:
require(['dompurify'], function(DOMPurify) {
var clean = DOMPurify.sanitize(dirty);
});
You can also grab the files straight from NPM:
(Note: DOMPurify doesn't work in Node.js yet, but runs fine with Browserify.)
npm install dompurify
var DOMPurify = require('dompurify');
var clean = DOMPurify.sanitize(dirty);
Of course there is a demo! Play with DOMPurify
How does purified markup look like? Well, the demo shows it for a big bunch of nasty elements. But let's also show some smaller examples!
DOMPurify.sanitize('<img src=x onerror=alert(1)//>'); // becomes <img src="x">
DOMPurify.sanitize('<svg><g/onload=alert(2)//<p>'); // becomes <svg><g></g></svg>
DOMPurify.sanitize('<p>abc<iframe/\/src=jAva	script:alert(3)>def'); // becomes <p>abc</p>
DOMPurify.sanitize('<math><mi//xlink:href="data:x,<script>alert(4)</script>">'); // becomes <math></math>
DOMPurify.sanitize('<TABLE><tr><td>HELLO</tr></TABL>'); // becomes <table><tbody><tr><td>HELLO</td></tr></tbody></table>
DOMPurify.sanitize('<UL><li><A HREF=//google.com>click</UL>'); // becomes <ul><li><a href="//google.com">click</a></li></ul>
DOMPurify currently supports HTML5, SVG and MathML. DOMPurify per default allows CSS, HTML custom data attributes. DOMPurify also supports the Shadow DOM - and sanitizes DOM templates recursively. DOMPurify also allows you to sanitize HTML for being used with the jQuery $() and elm.html() methods.
Yes. The included default configuration values are pretty good already - but you can of course override them. Check out the /demos folder to see a bunch of examples on how you can customize DOMPurify.
// allow only <b>
var clean = DOMPurify.sanitize(dirty, {ALLOWED_TAGS: ['b']});
// allow only <b> and <q> with style attributes (for whatever reason)
var clean = DOMPurify.sanitize(dirty, {ALLOWED_TAGS: ['b', 'q'], ALLOWED_ATTR: ['style']});
// leave all as it is but forbid <style>
var clean = DOMPurify.sanitize(dirty, {FORBID_TAGS: ['style']});
// leave all as it is but forbid style attributes
var clean = DOMPurify.sanitize(dirty, {FORBID_ATTR: ['style']});
// extend the existing array of allowed tags
var clean = DOMPurify.sanitize(dirty, {ADD_TAGS: ['my-tag']});
// extend the existing array of attributes
var clean = DOMPurify.sanitize(dirty, {ADD_ATTR: ['my-attr']});
// prohibit HTML5 data attributes (default is true)
var clean = DOMPurify.sanitize(dirty, {ALLOW_DATA_ATTR: false});
// return a DOM instead of an HTML string (default is false)
var clean = DOMPurify.sanitize(dirty, {RETURN_DOM: true});
// return entire document including <html> tags (default is false)
var clean = DOMPurify.sanitize(dirty, {WHOLE_DOCUMENT: true});
// make output safe for usage in jQuery's $()/html() method (default is false)
var clean = DOMPurify.sanitize(dirty, {SAFE_FOR_JQUERY: true});
// disable DOM Clobbering protection on output (default is true, handle with care!)
var clean = DOMPurify.sanitize(dirty, {SANITIZE_DOM: false});
// discard an element's content when the element is removed (default is true)
var clean = DOMPurify.sanitize(dirty, {KEEP_CONTENT: false});
DOMPurify allows you to augment its functionality by attaching one or more functions with the DOMPurify.addHook method to one of the following hooks:
beforeSantitizeElementsafterSantitizeElementsbeforeSantitizeAttributesafterSantitizeAttributesIt passes the currently processed DOM node and the DOMPurify configuration the callback.
Example:
DOMPurify.addHook('beforeSantitizeElements', function(currentNode, config) {
// Do something with the current node and return it
return currentNode;
});
To run the test suite, you need Node.js first. Install the dependencies with npm install, then start the test server with npm test. You can run the tests in your browser from http://localhost:8000/test/.
We maintain a mailing list that notifies whenever a security-critical release of DOMPurify was published. This means, if someone found a bypass and we fixed it with a release (which always happens when a bypass was found) a mail will go out to that list. This usually happens within minutes or few hours after learning about a bypass. The list can be subscribed to here:
https://lists.ruhr-uni-bochum.de/mailman/listinfo/dompurify-security
We recently implemented a Hook-API allowing developers to create their own DOMPurify plugins and customize its functionality without changing the core. Thus, we are looking forward for plugins and extensions - pull requests are welcome!
Several people need to be listed here! @garethheyes for invaluable help, @shafigullin for breaking the library multiple times and thereby strengthening it, @mmrupp and @irsdl for doing the same. Big thanks also go to @mathias, @cgvwzq, @robbertatwork, @giutro and @fhemberger!
FAQs
DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. It's written in JavaScript and works in all modern browsers (Safari, Opera (15+), Internet Explorer (10+), Firefox and Chrome - as well as almost anything else usin
We found that dompurify demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
Did you know?
Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.
Security News
Ransomware costs victims an estimated $30 billion per year and has gotten so out of control that global support for banning payments is gaining momentum.
Application Security
New SEC disclosure rules aim to enforce timely cyber incident reporting, but fear of job loss and inadequate resources lead to significant underreporting.
Security News
The Python Software Foundation has secured a 5-year sponsorship from Fastly that supports PSF's activities and events, most notably the security and reliability of the Python Package Index (PyPI).