function addListener(a,b,c,d){if(a.addEventListener){a.addEventListener(b,c,d);return true;}else if(a.attachEvent){var e=a.attachEvent("on"+b,c);return e;}else{alert("Handler could not be attached");}}

function bind(a,b,c,d){return window.addListener(a,b,function(){d.apply(c,arguments)});}

function handleKeystroke(evt) {             
	// Grab the cross browser event
	if( !evt ) evt = window.event;
		// Character code of key pressed
		var asc = !evt.keyCode ? (!evt.which ? evt.charCode : evt.which) : evt.keyCode;
		// ASCII character of above code
		var chr = String.fromCharCode(asc).toLowerCase();
		for (var i in this) {
			if (asc == i) {
				this[i](evt);
				break;
			}
		}
	}
	
function cancelEvent(evt) {
	evt.cancelBubble = true;
	evt.returnValue = false;
	if (evt.preventDefault) evt.preventDefault();
	if (evt.stopPropagation) evt.stopPropagation();
	return false;
}

//
// KEY COMMANDS
var keyMap = new Array();
var ARROW_RIGHT	= 39;
var ARROW_LEFT		= 37;

keyMap[ARROW_RIGHT] = pRight;
keyMap[ARROW_LEFT] = pLeft;

function pRight(evt) {
	nextImage();
}

function pLeft(evt) {
	previousImage();
}

// Add the keydown listner to the document object for global capture
bind(document, 'keydown', keyMap, handleKeystroke);