JS to determine the browser type code

<script language= "Web Effects" >
function Client (o) {

var B = navigator.useragent.tolowercase ();
var t = false;
if (o = = ' Isop ') {
t = B.indexof (' opera ') >-1;
}
if (o = = ' Isie ') {
t = b.indexof (' MSIE ') >-1;
}
if (o = = ' ISFF ') {
t = b.indexof (' Firefox ') >-1;
}
return t;
}
Alert (Client (' Isie '));
</script>

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Definitions and usage
The indexof () method returns the location of the first occurrence of a specified string value in a string.

Grammar
Stringobject.indexof (searchvalue,fromindex) parameter description
Searchvalue required. A string value that requires retrieval.
Fromindex an optional integer parameter. Specify where to start retrieving in the string. Its legal value is 0 to stringobject.length-1. If this argument is omitted, it is retrieved from the first character of the string.

Note: the IndexOf () method is case sensitive!

Note: If the string value to retrieve does not appear, the method returns-1.