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JavaScript Links

The first scenario discussed is the use of JavaScript code for navigation. A JavaScript link is any button

or text that, when clicked, navigates to another page. A typical JavaScript link looks like this:

<a href=”#“ onClick=”location.href=’http://www.example.com’; return false;”>Some

Text Here</a>

The primary objection to using this sort of link is its use of JavaScript where a regular link would suffice.

Doing so will typically prevent a search engine spider from following the links, and also prevent users who

disable JavaScript from navigating your site. Using them for

all

navigation may prevent a site from being

spidered at all. If you must use such links, provide alternative navigation somewhere else on the site.

The same issues would also be apparent in navigation involving other client-side dynamic technologies

such as Java applets, AJAX content, and Flash. In general, any navigation not achieved using a standard

anchor (

<a>)

tag will hinder site spidering.

Some webmasters have reported that spiders, especially Google, seem to be following some obvious-looking

JavaScript links in their sites. However, because this is the exception rather than the rule, depending on

this is not recommended.

By the same token, using JavaScript as a sort of page exclusion protocol, that is, assuming spiders do not

see or crawl links in JavaScript, is also unwise. Even if the JavaScript does achieve the end of obscuring

the link from spiders, other sites may link to the URL, which would likely get the page indexed regard-

less. If you don’t want a link to be indexed, you should exclude it using

robots.txt

or using the meta

exclusion tag.

DHTML Menus

Because they’re based on JavaScript, DHTML drop-down menus present problems for search engines

as well. It is wise to provide alternative navigation to all elements listed in the menus. You can do this

using a set of links at the bottom of the page, a sitemap, or a combination thereof. This way not only

search engines, but visitors with JavaScript support disabled, will be able to navigate the site with ease.

Many drop-down menus are somewhat spider-friendly, whereas others are not at all. The ones that are

not

tend to generate and display HTML on-the-fly using JavaScript. The ones that

are

typically hide and

unhide an HTML

div

element dynamically. The key here is that the HTML and links are actually pres-

ent, though hidden, in the document. Search engine algorithms may not, however, appreciate the hidden

aspect — rendering it an

invisible

on-page factor. It is wise to list the links

visibly

elsewhere in either case.

Popup Windows

The typical method of displaying popups employs JavaScript. And, as you learned, a search engine will

likely not spider a page only referred to by JavaScript. So what if you

do

want a popup to be indexed?

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Chapter 6: SE-Friendly HTML and JavaScript

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