function swapImg(aObj,id,imgObj) {
	var lists = aObj.parentNode.parentNode.getElementsByTagName('li');
	for(var i=0;i<lists.length;i++) {
		var a = lists[i].getElementsByTagName('a')[0];
		a.removeAttribute('class');
	}
	aObj.blur();
	
	var placeHolder = document.getElementById(imgObj);
	placeHolder.setAttribute('src','/_images/screenshot_'+id+'.jpg');
	aObj.setAttribute('class','on');
}