<script language="JavaScript">

bversion=parseInt(navigator.appVersion);

if (navigator.appVersion.indexOf('5.')>-1){

bversion=5

};

if (navigator.appVersion.indexOf('6.')>-1){

bversion=6

};

if (navigator.appVersion.indexOf('7.')>-1){

bversion=7

};

browsername='other browsers';

if (navigator.appName=='Netscape'){

browsername='NS'+version;

}

if (navigator.appName=='Microsoft Internet Explorer'){

browsername='MSIE'+version;

}

if(browsername == 'NS5'){

browsername='NS6'

};

//Internet Explorer

if (browser=='MSIE7') {

document.write('<link rel="stylesheet" type="text/css" href="/mie7.css">');

}
// set css file for other ie versions

//Netscape

if (browser=='NS4') {

document.write('<link rel="stylesheet" type="text/css" href="/nn4.css">');

}
//// set css file for other netscape versions

//other browsers

if (browser=='other browsers') {

document.write('<link rel="stylesheet" type="text/css" href="/others.css">');

}
</script>

you can also use the following comment for setting style sheet for
ie browsers instead of using javascript -

<!--[if IE]><style type="text/css">@import "ine_fix.css";</style><![endif]-->

only ie browsers will understand this line and use the css file.but
other browsers will just ignore the line and use the default css file.