Analysis of the difference between Javascript's addEventListener() and attachEvent()_javascript skills

In Mozilla:

How to use addEventListener:

target.addEventListener(type, listener, useCapture);

target: document node, document, window or XMLHttpRequest.
type: String, event name, excluding "on", such as "click", "mouseover", "keydown", etc.
listener: implements the EventListener interface or a function in JavaScript.
useCapture: Whether to use capture, usually false. For example: document.getElementById("testText").addEventListener("keydown", function (event) { alert(event.keyCode); }, false);

In IE:

target.attachEvent(type, listener);
target: document node, document, window or XMLHttpRequest.
type: String, event name, including "on", such as "onclick", "onmouseover", "onkeydown", etc.
listener: implements the EventListener interface or a function in JavaScript. For example: document.getElementById("txt").attachEvent("onclick",function(event){alert(event.keyCode);});

W3C and IE both support removing specified events, purpose It is an event to remove settings. The formats are as follows:

W3C format:

removeEventListener(event, function, capture/bubble);

The format of Windows IE is as follows:

detachEvent(event, function);


target.addEventListener(type, listener, useCapture);
target document node, document, window or XMLHttpRequest.
type string, event name, excluding "on", such as "click", "mouseover", "keydown", etc.
listener implements the EventListener interface or a function in JavaScript.
useCapture Whether to use capture, you will understand after reading the event flow section later. Generally, use false
When an event is triggered, an Event object will be passed to the event handler, such as:
document.getElementById ("testText").addEventListener("keydown", function (event) { alert(event.keyCode); }, false);
The browser versions adapted are different, and please pay attention during use
attachEvent method button onclick
addEventListener method button click used in IE
used in fox The principle of using both: the priority of execution can be different. The following examples are explained as follows:
attachEvent method, for a certain event Attach other processing events. (Mozilla series is not supported)
The addEventListener method is used in Mozilla series
Example: 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:
var btn1Obj = document.getElementById("btn1"); //object .attachEvent(event,function);
btn1Obj.attachEvent("onclick",method1);
btn1Obj.attachEvent("onclick",method2);
btn1Obj.attachEvent("onclick",method3); The execution order is method3->method2->method1
If it is the Mozilla series, this method is not supported, and you need to use addEventListener 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 order is method1->method2->method3
Example: (It should be noted that the div must be placed in front of js)