Tuning AJAX

"Asynchronous JavaScript and XML is becoming an increasingly pervasive deployment methodology, which necessitates that people start to both understand how it works and actually consider it more seriously as an enterprise-level development tool. To that end, I will try to illustrate one method of benchmarking your AJAX applications as well as point out some of the major performance pitfalls I have encountered while developing AJAX components and applications. When working with AJAX, it is paramount to understand that not only are there many different ways to update a web page but they also have varying levels of performance between browsers. Equally important to understand is that no matter how you update a web page, when you make changes to its (X)HTML content the parsing and rendering engine in the browser needs to update its internal representation of the page (recalculating the flow and layout) and then render the changes to the browser window -- for complex pages or changes this can take a considerable amount of time." Source: xml.com