CODEWITHSUNDEEP
javascriptdom
Udit Manektala
Udit Manektala

Reputation:

Can I find out from a Javascript method, who\which DOM element called me?

<a onclick ="foo()" href="bar.html" >Link </a>

<script>

...
function foo(){
  //I want to know the href property of whoever called me.
  //something like this.caller.href ??
}

</script>

I guess I could just assign all element IDs and then pass my own ID to the JS method I'm calling, but I was looking for a better way.

Upvotes: 16

Views: 19825

Answers (6)

Jim
Jim

Reputation: 601

<a onclick="foo(this)" href="bar.html">Link</a>

Then your JavaScript would be:

function foo(ob) {
    alert(ob.href); //or whatever you want to happen preferably pass an id 
}

Use the "this" selector if you want to pass the object itself to the function.

Upvotes: 11

Rex M
Rex M

Reputation: 144162

When the browser calls a function as the result of a DOM event, JavaScript passes an object to that function which contains information about the event. But it works a little differently in IE than others. To work in all browsers, foo() should take an argument* (I use e):

function foo(e) {
  var sender = (e && e.target) || (window.event && window.event.srcElement);
  //sender is the DOM element which was clicked
  alert(sender.href); //assumes the clicked element was an <a>
}

The first line will assign "sender" the value of the element which originated the event in all browsers.

Now, if your <a> contains child elements (for example, an image) and one of those was the actual element clicked, then that element will become the "sender". If this is a possibility, you need to walk up the DOM from the sender until you find your link:

function foo(e) {
  var sender = (e && e.target) || (window.event && window.event.srcElement);
  //sender is the DOM element which was clicked

  var myEle = sender;

  //find the parent node until we hit the <a>
  while(myEle.tagName.toUpperCase() != 'A') {
    myEle = myEle.parentNode;
  }

  //myEle is now the <a>. sender is still the originator.
  alert(myEle.href);
}

*You can also access any arguments passed to the function, even if they are not declared, by using the arguments[] array.

Upvotes: 19

PatrikAkerstrand
PatrikAkerstrand

Reputation: 45731

The convention here is that this refers to the DOM element that the handler is invoked on. So if you want to know the href of the link:

function foo () {
   // Inside foo this will refer to the DOM element if called as an event handler
   var href = this.href
}

That should do the trick.

EDIT: If foo is called from an onclick-handler explicitly in the DOM, i.e.

<a [...] onclick="foo()">

then the original context of this will be lost inside of foo. To fix this one can bind the function call to the original context:

<a [...] onclick="foo.call(this)">

Upvotes: 2

Omer Bokhari
Omer Bokhari

Reputation: 59648

you don't need to pass in the element as an argument to your function. you can use

var a = event.srcElement;
alert(a.href);

Upvotes: 0

Michael
Michael

Reputation: 35351

You could pass the value of the href attribute to the function when it is called:

<a href="http://www.example.com" onclick="foo(this.href)">link</a>

Upvotes: 1

Leonard Ehrenfried
Leonard Ehrenfried

Reputation: 1613

How about passing an argument?

foo(id);

Upvotes: 0

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