为所有子节点添加事件

Question

Why is that adding an event to the document.querySelector('li') works fine but Adding an event to the document.getElementsByTagName('li').childNodes Results in error and how to overcome this problem and attach events to all Its child nodes successfully, I know using childNodes creates an array but how do we add it. Should I use a for loop ?

Answer 1

You can add an event to an element but not to a collection.

You can access childNodes from an element but not a collection. Note that childNodes may include text nodes, which don't support event handlers.

What you want is document.querySelectorAll() , which creates a collection of elements based on a CSS selector .

You can iterate through the collection using a for loop, adding event listeners along the way:

 var nodes= document.querySelectorAll('li > *'); for(var i = 0 ; i < nodes.length ; i++) { nodes[i].addEventListener('click', function() { alert('You clicked ' + this.textContent); }); } 

 li * {background: orange;} 

 <ul> <li>Lorem <em>ipsum</em> dolor <strong>sit</strong> amet</li> <li>Consectetur <em>adipiscing</em> elit</li> <li>beatae <em>vitae</em> dicta <strong>sunt</strong></li> </ul> 

Answer 2

for(var element : document.getElementsByTagName('li')) {
  Event.observe(element, "click", function(){...});
}