common.js

function addEventHandler(obj, eventName, handler){
if(document.attachEvent){
obj.attachEvent("on" + eventName, handler);
}else if(document.addEventListener){
obj.addEventListener(eventName, handler, false);
}
}

function removeEventHandler(obj, eventName, handler){
if(document.detachEvent){
obj.detachEvent("on" + eventName, handler);
}else if(document.removeEventListener){
obj.removeEventListener(eventName, handler, false);
}
}