Rotating Text Banners: Fourth-Generation Browser Detection - Doc JavaScript
Fourth Generation Browser Detection
Our script utilizes JavaScript 1.2, first supported by Navigator 4.0x and Internet Explorer 4.0x, so we must make sure it does not affect users with older browsers.
There are two ways to determine which browser the user is running:
- You can evaluate
navigator.appVersion
ornavigator.userAgent
. - You can check if the browser supports specific objects (or properties) that the script requires.
The following script creates two Boolean variables that indicate whether the user is running Navigator 4.0x (or above) or Internet Explorer 4.0x (or above):
<SCRIPT LANGUAGE="JavaScript">
<!--
var bName = navigator.appName;
var bVer = parseInt(navigator.appVersion);
var NS4 = (bName == "Netscape" && bVer >= 4);
var IE4 = (bName == "Microsoft Internet Explorer" && bVer >= 4);
// -->
</SCRIPT>
The following script does the exact same by checking if the browser supports specific objects:
<SCRIPT LANGUAGE="JavaScript">
<!--
var NS4 = (document.layers) ? 1 : 0;
var IE4 = (document.all) ? 1 : 0;
// -->
</SCRIPT>
NS4
is true
if the browser supports the document.layers
object. In other words, it is true
for Navigator 4.0x. The second variable, IE4
, is true
if the browser supports the document.all
object. That is, it is true
for Internet Explorer 4.0x. Note that 1 and 0 are equivalent to true
and false
. We use them because they are shorter.
We'll use the second detection method in our scripts. By evaluating NS4
and IE4
we can find out if the user is running a fourth-generation browser:
<SCRIPT LANGUAGE="JavaScript">
<!--
var NS4 = (document.layers) ? 1 : 0;
var IE4 = (document.all) ? 1 : 0;
if (IE4 || NS4)
document.write("This is a fourth-generation browser!");
// -->
</SCRIPT>
This script simply prints "This is a fourth-generation browser!
" if the user is running Navigator 4.0x+ or Internet Explorer 4.0x+.
Created: September 25, 1997
Revised: April 16, 1998
URL: https://www.webreference.com/js/column3/detection.html