In our past installments on Web performance optimization, we’ve seen how caching, server configuration, and the use of Content Delivery Networks (CDNs) can increase a Web site’s responsiveness and improve Web performance metrics. Most of the techniques we’ve reviewed have focused on configuring the Web server or optimizing server applications. Unfortunately, a Web page that downloads quickly but is slow to parse or execute on the client will appear just as slow to a user as if the Web server were on its last megabyte of memory. In this article, we’ll discuss some ways that Web page content can be streamlined for an optimal client-side experience.
Streamline JavaScript Includes
JavaScript abounds on the Web. From jQuery to Dojo, the Web is full of JavaScript libraries that can easily be dropped into a Web application. And any site whose developers are actively adding features is going to accrue its own storehouse of .js files. Unless a site’s JavaScript is carefully managed, its Web pages could end up making a dozen or more separate requests for scripts. As we’ve already discussed in our article on
web performance optimization non-caching strategies, the more requests your site makes, the slower it will load.
Tip of the hat to TechAttitude.com for the graphic showing how Web page sizes and number of objects have grown tremendously over the past 16 years. In the interesting article they state, “…the average size of a web page has increased by more than five times since 2003” and “the use of mulitmedia is increasing by 100% each year”.
Follow these guidelines to manage and reduce the burden of JavaScript on your Web pages.