Getting Browser Name and Version in JavaScript

<script type="text/javascript">
var nVer = navigator.appVersion;
 var nAgt = navigator.userAgent;
 var browserName = navigator.appName;
 var fullVersion = ''+parseFloat(navigator.appVersion);
 var majorVersion = parseInt(navigator.appVersion,10);
 var nameOffset,verOffset,ix;
// In Opera, the true version is after "Opera" or after "Version"
 if ((verOffset=nAgt.indexOf("Opera"))!=-1) {
 browserName = "Opera";
 fullVersion = nAgt.substring(verOffset+6);
 if ((verOffset=nAgt.indexOf("Version"))!=-1)
 fullVersion = nAgt.substring(verOffset+8);
 }
 // In MSIE, the true version is after "MSIE" in userAgent
 else if ((verOffset=nAgt.indexOf("MSIE"))!=-1) {
 browserName = "Microsoft Internet Explorer";
 fullVersion = nAgt.substring(verOffset+5);
 }
 // In Chrome, the true version is after "Chrome"
 else if ((verOffset=nAgt.indexOf("Chrome"))!=-1) {
 browserName = "Chrome";
 fullVersion = nAgt.substring(verOffset+7);
 }
 // In Safari, the true version is after "Safari" or after "Version"
 else if ((verOffset=nAgt.indexOf("Safari"))!=-1) {
 browserName = "Safari";
 fullVersion = nAgt.substring(verOffset+7);
 if ((verOffset=nAgt.indexOf("Version"))!=-1)
 fullVersion = nAgt.substring(verOffset+8);
 }
 // In Firefox, the true version is after "Firefox"
 else if ((verOffset=nAgt.indexOf("Firefox"))!=-1) {
 browserName = "Firefox";
 fullVersion = nAgt.substring(verOffset+8);
 }
 // In most other browsers, "name/version" is at the end of userAgent
 else if ( (nameOffset=nAgt.lastIndexOf(' ')+1) <
 (verOffset=nAgt.lastIndexOf('/')) )
 {
 browserName = nAgt.substring(nameOffset,verOffset);
 fullVersion = nAgt.substring(verOffset+1);
 if (browserName.toLowerCase()==browserName.toUpperCase()) {
 browserName = navigator.appName;
 }
 }
 // trim the fullVersion string at semicolon/space if present
 if ((ix=fullVersion.indexOf(";"))!=-1)
 fullVersion=fullVersion.substring(0,ix);
 if ((ix=fullVersion.indexOf(" "))!=-1)
 fullVersion=fullVersion.substring(0,ix);
majorVersion = parseInt(''+fullVersion,10);
 if (isNaN(majorVersion)) {
 fullVersion = ''+parseFloat(navigator.appVersion);
 majorVersion = parseInt(navigator.appVersion,10);
 }
document.write(''
 +'Browser name = '+browserName+'<br>'
 +'Full version = '+fullVersion+'<br>'
 +'Major version = '+majorVersion+'<br>'
 +'navigator.appName = '+navigator.appName+'<br>'
 +'navigator.userAgent = '+navigator.userAgent+'<br>'
 )
</script>