Accessing DOM elements without id

问题

i have a page around 500 div as below.

<div onclick='test()' class='test>
     <ul class='innermenu'>
       <li>1</li>
       .....
      </ul>
  </div>

when the test function is called it need to hide the menu (innermenu) who calls that function.

my problems are

uniquely identify the div without using id
How to hide only the particular ul alone.

回答1:

OK, first the quick fix, though it is not the best way to use JS on your page:

Change the call to this:

<div onclick="test(this);" class="test">

Then, in test, use this:

function test(el){
   var uls = el.getElementsByTagName('ul');
   for(var i = 0; i < uls.length; i++){
      if(uls[i].className == 'innermenu'){
         uls[i].style.display = "none";
         break;
      }
   }
}

This will hide just the child ul of the div that is clicked.

A better way

OK, for the longer answer. Either attach the events after the fact using attachEvent and addEventListener or use a library like jQuery to help you out. Here is the raw solution:

Set up your HTML this way (no onclick):

<div class="test">

And then at the very end of your HTML put this:

<script type="text/javascript">
    var divs = document.getElementsByTagName('div');
    function test(){
      var uls = this.getElementsByTagName('ul');
      for(var i = 0; i < uls.length; i++){
         if(uls[i].className == 'innermenu'){
            uls[i].style.display = "none";
            break;
         }
      }
    };

    for(var i = 0; i < divs.length; i++){
      var div = divs[i];
      if(div.className !== "test") continue;
      if(window.addEventListener){
         div.addEventListener( 'click', test, true ); //FF, Webkit, etc
      } else if (window.attachEvent) {
         div.attachEvent('onclick', test); // IE
      } else {
         div.onclick = test; // Fallback
      }
    }
</script>

Now, you don't have JavaScript code in your HTML, and you can get rid of the extra parameter on the test function.

回答2:

There is a method

document.getElementsByClassName

but it isn't supported in all browsers.

javascript

function test(elem)
{
    var childElem = elem.children[0];
    childElem.style.display = 'none';
}

<div onclick='test(this)' class='test'>
    <ul class='innermenu'>
        <li>1</li>
        <li>2</li>
    </ul>
</div>

If you can use jQuery then you can do something like this

$("div.test").click(function(){
    $(this).find("ul.innermenu").hide();
});

回答3:

If you don't want assign ids, you can try this to hide the div which gets clicked:

<div onclick="hideMe(this);" class='test>

<script>
 function hideMe(elem)
 {
   elem.style.display = 'none';
 }
</script>

回答4:

Try passing "this" as parameter:

<div onclick='test(this)' class='test>
 <ul class='innermenu'>
   <li>1</li>
   .....
  </ul>

 function test(sender) {
        //sender is DOM element that is clicked
        alert(sender.id);
    }

回答5:

If getElementsByClassName is not supported by all browsers as mentioned by @rahul, you can iterate through the dom and find it yourself - provided there is only one <ul> with class name "innermenu"

var uls = document.body.getElementsByTagName("ul");
var len = uls.length;
for(var i = 0; i < len; i++)
{
  var ul = uls.item(i);
  if(ul.getAttribute("class") == "innermenu")
  {
    ul.style.display = "none";
    break;
  }
}

来源：https://stackoverflow.com/questions/2332061/accessing-dom-elements-without-id

标签

javascript

dom