How to use javascript attachEvent and addEventListener_javascript skills

attachEvent method button onclick
addEventListener method button click
The principle of using both: they can have different execution priorities. The following examples are explained as follows:
attachEvent method attaches other processing events to a certain event. (Mozilla series is not supported)
addEventListener method is used for Mozilla series
Example:
Java code

Copy code The code is as follows:

document.getElementById("btn").onclick = method1;
document.getElementById("btn").onclick = method2;
document.getElementById(" btn").onclick = method3;

If written like this, then only medhot3 will be executed
Written like this:
Java code:

Copy code The code is as follows:

var btn1Obj = document.getElementById("btn1");
//object.attachEvent(event ,function);
btn1Obj.attachEvent("onclick",method1);
btn1Obj.attachEvent("onclick",method2);
btn1Obj.attachEvent("onclick",method3);

The execution sequence is method3->method2->method1
If it is the Mozilla series, this method is not supported, and you need to use addEventListener
Java code:

Copy code The code is as follows:

var btn1Obj = document.getElementById("btn1");
//element.addEventListener( type,listener,useCapture);
btn1Obj.addEventListener("click",method1,false);
btn1Obj.addEventListener("click",method2,false);
btn1Obj.addEventListener("click", method3,false);

The execution sequence is method1->method2->method3
Usage example:
1. Java code:

Copy code The code is as follows:

var el = EDITFORM_DOCUMENT.body;
//Get the object first, EDITFORM_DOCUMENT is actually an iframe
if (el.addEventListener)...{
el.addEventListener('click', KindDisableMenu, false);
} else if (el. attachEvent)...{
el.attachEvent('onclick', KindDisableMenu);
}

2. Java code:

Copy code The code is as follows:

if (window.addEventListener){
window.addEventListener('load', _uCO, false);
} else if (window.attachEvent){
window.attachEvent('onload', _uCO);
}