JavaScript and Search Engine Optimization (SEO)

JavaScript is often used in drop-down and slide-out navigation on websites. These types of navigation are referred to as “JavaScript menus.” The issue with using JavaScript menus is that most search engines cannot read them or follow the links inside the JavaScript code. A few search engines can read a minimal amount of JavaScript. Even-though they may be able to read and identify some links in JavaScript code, they cannot execute the code, and therefore the links cannot be followed. Search engine spiders are designed to read and then follow basic HTML hyperlinks. Because they simply cannot follow most JavaScript links, if a spider cannot find the pages in a site, those pages will never show up in search results.

Search engines have also penalized web sites that use JavaScript redirects. JavaScript redirects can sometimes be used to point a user to a new page when a page file name is changed or the page is moved. It’s never a good idea to use a JavaScript redirect to do this. Google is especially hard on websites that use JavaScript redirects. When their search engine spiders crawl a website and detect the redirect, that site is often banned from Google’s directory. Because Google commands about 50% of all search engine traffic, it’s a good idea to avoid redirecting pages using JavaScript.