Spring Sale! Save 30% on all books w/ code: PLANET24
Web Dev + WordPress + Security

JavaScript Notes Plus

Welcome to Perishable Press! This article covers a plethora of useful JavaScript tips and tricks. For more excellent JavaScript information, check out the JavaScript tag archive. If you like what you see, I encourage you to subscribe to Perishable Press for a periodic dose of online enlightenment ;)

Nifty JavaScript Design Tricks

Clickable divs

Standard design practice dictates that the site logo or banner located at the top of the page links to the home page of the site. There are several methods for including such functionality into a design, including this JavaScript trick that transforms an entire element (e.g., any div) into a link pointing to the site root:

<div id="banner" onclick="location.href='/';" style="cursor:pointer;">
   [ content goes here ]
</div>

Hide/Validate JavaScript Code

JavaScript Comments

Commenting your scripts is an excellent and highly recommended practice. Here are two methods of commenting within a block of JavaScript.

<script type="text/javascript">

// Use two forward slashes for single line comments

/* Use this method for
multi-line comments */

</script>

Link to an External JavaScript File

This is the preferred method of including JavaScript files. It is invisible to non-JavaScript browsers, and keeps the document from breaking during validation. Use if possible.

<script src="external.js" type="text/javascript"></script>

Hiding JavaScript

Hiding JavaScript code from non-compliant browsers is rather easy, just employ the following lines of code:

<script type="text/javascript">
<!--

JavaScript goes here
JavaScript goes here

//-->
</script>

Unfortunately, JavaScript code does not validate as XHTML. Fortunately, it is possible to present your code as invisible to the validators by enveloping it with the following lines of code:

<script type="text/javascript">
<![CDATA[

JavaScript goes here
JavaScript goes here

]]>
</script>
Combining these two methods produces a deadly weapon in the hellish JavaScript battle:
<script type="text/javascript">
<!--//--><![CDATA[//><!--

JavaScript goes here
JavaScript goes here

//--><!]]>
</script>

And, an alternate method has been suggested, but sustains inconsistent consensus:

<script type="text/javascript">
/* <![CDATA[ */

JavaScript goes here
JavaScript goes here

/* ]]> */
</script>

Here is the same commenting method used for CSS:

<style type="text/css">
/* <![CDATA[ */

CSS goes here
CSS goes here

/* ]]> */
</style>

A slightly modified version of the previous method:

<style type="text/css">
/* //<![CDATA[ */
<!--

CSS goes here
CSS goes here

//-->
/* //]]> */
</style>
Here is yet another way to comment out CSS content:
<style type="text/css">
<!--/*--><![CDATA[/*><!--*/

CSS goes here
CSS goes here

/*]]>*/-->
</style>

Finally, although popular, avoiding this method has been recommended:

<script type="text/javascript">
//<![CDATA[
<!--

JavaScript goes here
JavaScript goes here

//-->
//]]>
</script>

Non-JavaScript Browser Support

Use the <noscript> tag to provide support for antiquated browsers and serve 'em some alternate content. The <noscript> tag operates according to the presence/absence of JavaScript. Consider the following:

<noscript>
 <p>This will not be displayed if JavaScript is enabled.</p>
</noscript>

Here is a specific example that would provide a user with the option to continue browsing without JavaScript:

<noscript>
 <p>
  It appears your browser doesn't support JavaScript.
  Please visit <a href="http://domain.tld/noscript.html">the no-script page</a>
  to see a non-JavaScript version of this page.
 </p>
</noscript>

About the Author
Jeff Starr = Web Developer. Book Author. Secretly Important.
Blackhole Pro: Trap bad bots in a virtual black hole.
Welcome
Perishable Press is operated by Jeff Starr, a professional web developer and book author with two decades of experience. Here you will find posts about web development, WordPress, security, and more »
GA Pro: Add Google Analytics to WordPress like a pro.
Thoughts
I live right next door to the absolute loudest car in town. And the owner loves to drive it.
8G Firewall now out of beta testing, ready for use on production sites.
It's all about that ad revenue baby.
Note to self: encrypting 500 GB of data on my iMac takes around 8 hours.
Getting back into things after a bit of a break. Currently 7° F outside. Chillz.
2024 is going to make 2020 look like a vacation. Prepare accordingly.
First snow of the year :)
Newsletter
Get news, updates, deals & tips via email.
Email kept private. Easy unsubscribe anytime.