jsDOM is a benchmark suite for measuring performance of JavaScript DOM manipulation. That is, it does not measure the speed of the JavaScript interpreter itself, but rather the speed of the web browsers interface with JavaScript. In many modern web applications, this is the largest performance bottleneck.

It is important to note the scope of jsDOM. What this benchmark tests is how fast the web browser is in creating new DOM objects in response to JavaScript requests. This benchmark does not measure how fast the browser then is at actually painting things on screen. Just because a script has created a new table does not imply that the browser chooses to display it on screen. There is, to the best of my knowledge, no sane way to check this.

Many additional tests could be added. Patches are welcome.

jsDOM relies heavily on the jQuery library for DOM manipulation. The reasoning behind this choice is that jQuery is a popular real world choice, and as such, the benchmark should better reflect real world performance.

The jsDOM test performs a set of tasks that are all reasonable to expect an AJAX heavy site to perform during initial loading. These tasks include creating DOM nodes using one of several techniques, creating a form, and modifying the styling of DOM elements in several ways. The average time taken to complete all these tasks once is inverted to produce the final benchmark score. In other words, a score of ten means that the DOM manipulation portion of page loading can be expected to take roughly one tenth of a second. This is the threshold chosen for what is percieved to be acceptable performance in this benchmark.

jsDOM relies heavily on various open source libraries that are distributed together with this software.

• jQuery is Copyright (c) 2009 John Resig
• flot is Copyright (c) 2007-2009 IOLA and Ole Laursen
• ExplorerCanvas is Copyright (c) 2006 Google Inc.

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