Simon Willison’s Weblog

Blogmarks tagged javascript, firefox in 2008

Filters: Type: blogmark × Year: 2008 × javascript × firefox ×

ReferenceError: console is not defined. Since Firebug 1.2 you need to call window.loadFirebugConsole() in order for console.log and friends to work. # 23rd December 2008, 10:22 pm

Browser Paint Events. The latest Firefox nightlies include a new MozAfterPaint event which fires after a portion of the page has been redrawn and provides co-ordinates of the affected rectangle. John Resig provides a neat bookmarklet that uses the new event to visualise repainting operations. # 14th October 2008, 1:08 pm

querySelectorAll in Firefox 3.1. John Resig benchmarks the various JavaScript libraries’ support for querySelelectorAll, and finds an impressive 2-6x performance improvement over native DOM traversal. It’s worth clicking through to John’s experimental plugin for adding support to jQuery, which does a clever trick using __proto__ to convert the collection returned by querySelectorAll in to a jQuery object in browsers that support it. # 21st August 2008, 9:50 am

eval() Kerfuffle. The ability to read supposedly private variables in Firefox using a second argument to eval() will be removed in Firefox 3.1. # 2nd July 2008, 9:24 pm

Javascript protocol fuzz results. If your HTML sanitizer uses blacklisting rather than whitelisting here are a few more weird ways of injecting javascript: in to a link that you need to worry about—but you should really switch to whitelisting http:// and https:// instead. # 30th June 2008, 3:57 pm

Module Pattern Provides No Privacy... at least not in JavaScript(TM) (via) JavaScript variables hidden inside a closure aren’t as hidden as I thought—it turns out you can pass a closure as the second argument to eval (at least in Firefox) and “steal” private variables back out of it. # 27th June 2008, 7:01 pm

Reading binary files using Ajax. There’s a simple trick for Firefox, and (amazingly) you can get IE to play along using a function written in VBScript. # 22nd April 2008, 7:02 pm

Cross-Window Messaging. Now in Firefox 3 trunk, the HTML 5 specified ability for JavaScript to send messages between windows (or iframes) hosted on different domains. Fantastically powerful, but must be implemented with care to avoid accidentally processing bad messages from malicious third parties. # 10th February 2008, 12 pm

Cross-Site XMLHttpRequest (via) “Firefox 3 implements the W3C Access Control working draft, which gives you the ability to do XMLHttpRequests to other web sites”—you can mark a document as available for cross-domain requests using either an Access-Control HTTP header or an XML processing instruction. # 9th January 2008, 11:57 pm