如何在Javascript中添加事件处理程序？

Question

I have a listener on DOMContentLoaded which calls startup() function.

I want to add more listeners (within the startup function) to items added to the DOM in the startup function. But it seems to fail (no click event registetered)

I use item.addEventListener("click", f, false); where f is the function that is supposed to run.

NOTE: I CANNOT use onclick=... I also cannot use JQuery.

Demo code is here

Answer 1

You have several issues in your code:

1. previous function is not defined
2. To attach a click event via addEventListener, the event name is click not onclick .
3. You are calling addListeners outside of your load function.

Here is a jsfiddle that works: http://jsfiddle.net/VUgRu/

You should always use the javascript console to see what errors you are getting.

Answer 2

Using no frameworks (no excuse to use them) and adding an event listener in standard compliant browsers and Internet Explorer 8 and older for attachEvent...

 if (window.addEventListener) {document.addEventListener('keydown',keyPressed,false);}
 else {document.attachEvent('onkeydown',keyPressed);}

function keyPressed(evt)
{
 var e = evt || event;
 var key = e.which || e.keyCode;

 switch (key)
 {
  case 77:// M
  alert('m key pressed');
  break;

  case 76://L
  alert('L key pressed');
  break;
 }
}