function changeClass(id,maClass) {
	if((id && 'object' == typeof id) || 'function' == typeof(id)) {
		id.className = maClass;
	} else {
		document.getElementById(id).className = maClass;
	}
	return false;
}

var popup_img_window = null;

function addPopupEvent(){
    var objNodes=document.getElementsByTagName("A");

    for(var i = 0; i < objNodes.length; i++) {
		if (objNodes[i].className == 'popup_img') {

			objNodes[i].onclick = function() {
			    var src = this.href;

			    if (!popup_img_window || popup_img_window.closed) {
			        popup_img_window = window.open('/img_popup.php?img_url='+src, 'img_window', 'location=0');
			    } else {
			        popup_img_window.location = '/img_popup.php?img_url='+src;
			        popup_img_window.focus();
			    }
			    return false;

			}
		}
	}
}