How do I detect whether a browser supports mouseover events?

var supportsTouch = (typeof Touch == "object");

Just detect if it's a touch device and then do your special stuff. This is the simplest approach since most touch devices emulate mouse events but no mouse driven device emulates touch events.

Update: Considering how many devices there are now a days and Johan's comments I'd recommend simply using Modernizr.

This method catches more devices/browsers

try {
   document.createEvent("TouchEvent");
   alert(true);
}
catch (e) {
   alert(false);
}

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