JavaScript: Event type, returns appropriate event type for device based on the parameter passed to it

gistfile1.js

// Function returns appropriate event type for device based
// on the parameter passed to the function
var et = function(t) {
	var msPointer = window.navigator.msPointerEnabled;
	var isTouchDevice = (typeof(window.ontouchstart) != 'undefined') ? true : false;
	var clickArray = ['c','click','mousedown','down','touchstart'];
	var releaseArray = ['r','release','up','mouseup','touchend'];
	var moveArray = ['m','move','mousemove','touchmove','drag'];
	var eventType = '';

	if (clickArray.indexOf(t) > -1) {
		eventType = (isTouchDevice) ? 'touchstart' : eventType;
		eventType = (msPointer) ? 'MSPointerDown' : eventType;
		eventType = (!eventType) ? 'mousedown' : eventType;
		//return (isTouchDevice) ? 'touchstart' : 'mousedown';
	}
	if (releaseArray.indexOf(t) > -1) {
		eventType = (isTouchDevice) ? 'touchend' : eventType;
		eventType = (msPointer) ? 'MSPointerUp' : eventType;
		eventType = (!eventType) ? 'mouseup' : eventType;
		//return (isTouchDevice) ? 'touchend' : 'mouseup';
	}
	if (moveArray.indexOf(t) > -1) {
		eventType = (isTouchDevice) ? 'touchmove' : eventType;
		eventType = (msPointer) ? 'MSPointerMove' : eventType;
		eventType = (!eventType) ? 'mousemove' : eventType;
		//return (isTouchDevice) ? 'touchmove' : 'mousemove';
	}

	if (eventType) return eventType;
	alert('Please pass et() a paramater it can use.');
}