Attachevent ()/addeventlistener () object addition trigger event

Attachevent ()/addeventlistener () object addition trigger event

Sometimes, when an event of an object is triggered, the program to be executed may be a large string, or it may call a function, it is also possible to call another function at the same time.

Document. getelementbyid ("BTN"). onclick = Method1;
Document. getelementbyid ("BTN"). onclick = method2;
Document. getelementbyid ("BTN"). onclick = method3;
If this is the case, only medhot3 will be executed.

Use addachevent in IE,

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

Addeventlistener must be used in the Mozilla Series

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

Look at the Gmail code.

VaR Ka = navigator. useragent. tolowercase ();
VaR RT = ka. indexof ("Opera ")! =-1;
VaR r = ka. indexof ("MSIE ")! =-1 & (document. All &&! RT );

Function ZL (a, B, c) {If (r) {. attachevent ("On" + B, c)} else {. addeventlistener (B, c, false )}}