Javascript Browser checking

Javascript Browser checking:
This piece of javascript code will check which browser (and version) your user is running.

var browserName = navigator.appName;
var browserVersion = navigator.appVersion;
var browserVersionNum = parseFloat(browserVersion);

function detectbrowser()
{
BrowserInfo = " (Your browser is " + browserName + " " + browserVersionNum +")";
alert(compatible + BrowserInfo);
}
<body>
<a href="javascript:detectbrowser()">Checkbrowser</a>
</body>
</html>