<script> (X)HTML Element Reference :: webDev

Use Correct <script> Tags

The LANGUAGE attribute is deprecated in the <script> tag. The proper way to create a javascript code block is:

<script type="text/javascript">
// code here
</script>

Including JavaScript In XHTML: External, DOM Created, CDATA & Comments :: CSS, JavaScript And XHTML Explained

Even when src is specified, the script tag is not an empty tag, and cannot be written will prevent the download of other page components until the .js file has been retrieved, compiled and executed. Placing the .js at the end of the body can improve both perceived and actual download time. However, if rendering the page requires functions from the javascript, include the javascript before the page calls required functions.

The defer attribute – written defer="defer" in XHTML – is a fairly useless attribute of the script tag. It tells the browser that the script does not create any content allowing the browser to defer interpreting the script. The delaying of execution of scripts until after the body content is parsed and rendered is optional for the browser, and the browser still downloads the script, putting download of all other elements on hold, so unless there is a reason to include the script earlier in the page, the recommendation is to place the external script call immediately before the .

runat="server" is an optional attribute/value. I haven’t ever used it, so can’t really comment on it. I assume it’s used for non-javascript scripts and for ASP.net javascripts, telling the server to run the script, or, in the case of any element in ASP.net, on the server.

3. Load your CSS first and your JavaScript last

With some websites, you simply can’t get around all the HTTP requests, as it disrupts your functionality. So as an alternative, you can "bring out the appetizer" while the "main entree" is finishing up by loading the JavaScript files last.

• In that regard, here’s a couple of tips:
• 1. Load your CSS in your tag above your body.
• 2. Load your JavaScript just before you close your tag.

What happens is that the page appears to be loaded on the user’s machine, so their eyes can begin scanning the offerings, all the while the JavaScript is catching up in the rears and loading in the background.

Tip: If you don’t want to physically move the JavaScript tags, as you feel it will mess up the way your site works, I recommend using the defer property. usage is as follows:

 <script defer='defer'>