How to identify the browser's JavaScript engine

= function() {
var v8string = 'function%20javaEnabled%28%29%20%7B%20%5Bnative%20code%5D%20%7D';

if () //If WebKit browser
{
if (escape(()) === v8string)
{
display('V8 detected');
}
else
{
display('JSC detected');
}
}
else {
display("Not a WebKit browser");
}

function display(msg) {
var p = ('p');
= msg;
(p);
}

};