javascript not work on ajax content

有经验的人回答了：

When you initially created the .click() handler, that second button was not yet in the DOM, so jQuery could not attach an event handler to it. The .live() function will work for any element that is already in the DOM and also any element that will be added in the future (e.g. from an ajax call).

This, however, seems to me to be much more explicit about what is actually happening. You don‘t realise from the live example that the events are actually being captured on document; with delegate, it is clear that the event capturing happens on #containerElement. You can do the same thing with live, but the syntax becomes increasingly horrid.

Specifying a context for your events to be captured also improves performance. With the live example, every single click on the entire document has to be compared with the selector a.myClass to see if it matches. With delegate, that is only the elements within #containerElement. This will obviously improve performance.

Finally, live requires that your browser looks for a.myClass whether or not it currently exists. delegate only looks for the elements when the events are triggered, giving a further performance advantage.

NB delegate uses live behind the scenes, so you can do anything with live that you can do with delegate. My answer deals with them as they are commonly used.

Note also that neither live nor delegate is the best way to do event delegation in modern jQuery. The new syntax (as of jQuery 1.7) is with the on function. The syntax is as follows:

 jQuery(‘.ajaxCommentMiniList‘).on(‘click‘, ‘.pagination a‘,function(){

		ajaxCommentMiniList.clickAction(jQuery(this));		
		return false;
	});