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When Netscape Navigator 3 was released with the JavaScript 1.1 engine, one major improvement was the introduction of the SRC= attribute for the <SCRIPT> tag.
At the time, the Release Notes described the new attribute in this way:
SRC attribute: The <SCRIPT> tag now has an additional attribute that allows a JavaScript file to be specified as the JavaScript source (rather than embedding the JavaScript in the HTML). Attributes within the SCRIPT tag can now be specified as follows:
<SCRIPT LANGUAGE="JavaScript" SRC="mySource.js">
where mySource.js is the URL (relative or full address) of the JavaScript source code file.
The SRC attribute specifies the scripting language by using the .js suffix. The suffix must be mapped by the web server to the MIME type "application/x-javascript"
. . .
from the Navigator 3.0 Release Notes
With Navigator 4, we had the introduction of DHTML and JavaScript 1.2. We could, therefore, specify DHTML-specific scripts by using a value of JavaScript1.2 value for the LANGUAGE= attribute:
<SCRIPT LANGUAGE="JavaScript1.2">
Older browsers would not recognize the attribute value and ignore the script.
Explorer 4, while not being 100% compatible with JavaScript 1.2, also recognized the JavaScript1.2 value. We could therefore safely include scripts to be read only by DHTML browsers, if we specified JavaScript1.2 as the LANGUAGE.
It follows that external scripts can be conditionally loaded for DHTML browsers by using this syntax:
<SCRIPT LANGUAGE="JavaScript1.2" SRC="myDHTMLSource.js">
You will have noticed that here at DHTML Lab, we load external JS files for DHTML browsers with this syntax:
<SCRIPT LANGUAGE="JavaScript1.2" TYPE="text/javascript">
<!--
document.write("<SCRIPT LANGUAGE='JavaScript1.2' SRC='myDHTMLSource.js' TYPE="text/javascript"><\/SCRIPT>");
//-->
</SCRIPT>
If you have read all our columns, you will be aware of the reasons for this awkward and, seemingly, overly verbose syntax.
If not, this short article will explain why we use our syntax and not the documented syntax. Along the way, we'll also explore several browser bugs and quirks.
First, we need to look at a problem with Navigator 3.
Produced by Peter Belesis and
All Rights Reserved. Legal Notices.
Created: Nov 2, 1999
Revised: Nov 2, 1999
URL: http://www.webreference.com/dhtml/diner/scriptsrc/
