JavaScript Version Example

This example shows how you can check which version of JavaScript that is available and how to structure your code

Please note that JavaScript is currently only available in Netscape Navigator 2.0 and Explorer 3.01 or higher. Do not assume that all in your audience are using a JavaScript enabled browser.

Here is an example on how the SCRIPT LANGUAGE tag can be used to separate JavaScript commands for different versions of the browser. This JavaScript example can be used freely by registered PageSpinner users. You can also use PageSpinner's JavaScript menu where you find the SCRIPT LANGUAGE tags currently supported by Navigator 4.0x and earlier versions.

Inside the script tag enclosing the script you can specify which version of JavaScript that is required for the commands to work. When the page is loaded, older browser which don't handle JavaScript 1.1 or 1.2 will ignore the statements inside these sections:

<SCRIPT LANGUAGE="JavaScript"> This code will always be performed if JavaScript is available.
<SCRIPT LANGUAGE="JavaScript1.1"> The code inside this script tag will only be performed in Navigator 3.0, Explorer 3.01 and later versions.
<SCRIPT LANGUAGE="JavaScript1.2"> The code inside this script tag will only be performed in Navigator 4.0, Explorer 4.0 and later versions.

The following code section: 

<SCRIPT LANGUAGE="JavaScript">
<!-- Beginning of JavaScript -

var	theText	= "";
var	jsVersion = "1.0"
	theText = "JavaScript Version 1.0 is always available";

// - End of JavaScript - -->
</SCRIPT>

<SCRIPT LANGUAGE="JavaScript1.1">
<!-- Beginning of JavaScript -
	jsVersion = "1.1"

	theText = theText + "<BR>This line is displayed in a browser that supports JavaScript Version 1.1";


// - End of JavaScript - -->
</SCRIPT>

<SCRIPT LANGUAGE="JavaScript1.2">
<!-- Beginning of JavaScript -
	jsVersion = "1.2"

	theText = theText + "<BR>This line is displayed in a browser which supports JavaScript Version 1.2";
	
// - End of JavaScript - -->
</SCRIPT>

will produce the following result in your browser:

How to use

If you have code that only works in Navigator 3 or 4, you should place the code inside the JavaScript1.1 or the JavaScript1.2 script tag. This enables you to use new JavaScript statements without getting syntax errors in older browsers.

To know which version of JavaScript that is available, in e.g. event handlers, you can check the value of the variable jsVersion if you use the JavaScript sections in this example as a template for your JavaScript-enhanced pages:

Simple example: 

if (jsVersion == "1.0")
{
	document.bgColor = "#EEEEEE";
}