How to stop event propagation with inline onclick attribute?

Consider the following:

<div onclick="alert('you clicked the header')" class="header">
  <span onclick="alert('you clicked inside the header');">something inside the header</span>
</div>

How can I make it so that when the user clicks the span, it does not fire the div's click event?

Use event.stopPropagation().

<span onclick="event.stopPropagation(); alert('you clicked inside the header');">something inside the header</span>

For IE: window.event.cancelBubble = true

<span onclick="window.event.cancelBubble = true; alert('you clicked inside the header');">something inside the header</span>

There are two ways to get the event object from inside a function:

1. The first argument, in a W3C-compliant browser (Chrome, Firefox, Safari, IE9+)
2. The window.event object in Internet Explorer (<=8)

If you need to support legacy browsers that don't follow the W3C recommendations, generally inside a function you would use something like the following:

function(e) {
  var event = e || window.event;
  [...];
}

which would check first one, and then the other and store whichever was found inside the event variable. However in an inline event handler there isn't an e object to use. In that case you have to take advantage of the arguments collection which is always available and refers to the complete set of arguments passed to a function:

onclick="var event = arguments[0] || window.event; [...]"

However, generally speaking you should be avoiding inline event handlers if you need to to anything complicated like stopping propagation. Writing your event handlers separately and the attaching them to elements is a much better idea in the medium and long term, both for readability and maintainability.

Keep in mind that window.event is not supported in FireFox, and therefore it must be something along the lines of:

e.cancelBubble = true

Or, you can use the W3C standard for FireFox:

e.stopPropagation();

If you want to get fancy, you can do this:

function myEventHandler(e)
{
    if (!e)
      e = window.event;
    
    //IE9 & Other Browsers
    if (e.stopPropagation) {
      e.stopPropagation();
    }
    //IE8 and Lower
    else {
      e.cancelBubble = true;
    }
}

Use this function, it will test for the existence of the correct method.

function disabledEventPropagation(event)
{
   if (event.stopPropagation){
       event.stopPropagation();
   }
   else if(window.event){
      window.event.cancelBubble=true;
   }
}

I had the same issue - js error box in IE - this works fine in all browsers as far as I can see (event.cancelBubble=true does the job in IE)

onClick="if(event.stopPropagation){event.stopPropagation();}event.cancelBubble=true;"

This worked for me

<script>
function cancelBubble(e) {
 var evt = e ? e:window.event;
 if (evt.stopPropagation)    evt.stopPropagation();
 if (evt.cancelBubble!=null) evt.cancelBubble = true;
}
</script>

<div onclick="alert('Click!')">
  <div onclick="cancelBubble(event)">Something inside the other div</div>
</div>

For ASP.NET web pages (not MVC), you can use Sys.UI.DomEvent object as wrapper of native event.

<div onclick="event.stopPropagation();" ...

or, pass event as a parameter to inner function:

<div onclick="someFunction(event);" ...

and in someFunction:

function someFunction(event){
    event.stopPropagation(); // here Sys.UI.DomEvent.stopPropagation() method is used
    // other onclick logic
}

According to this page, in IE you need:

event.cancelBubble = true

I cannot comment because of Karma so I write this as whole answer: According to the answer of Gareth (var e = arguments[0] || window.event; [...]) I used this oneliner inline on the onclick for a fast hack:

<div onclick="(arguments[0] || window.event).stopPropagation();">..</div>

I know it's late but I wanted to let you know that this works in one line. The braces return an event which has the stopPropagation-function attached in both cases, so I tried to encapsulate them in braces like in an if and....it works. :)

Why not just check which element was clicked? If you click on something, window.event.target is assigned to the element which was clicked, and the clicked element can also be passed as an argument.

If the target and element aren't equal, it was an event that propagated up.

function myfunc(el){
  if (window.event.target === el){
      // perform action
  }
}
<div onclick="myfunc(this)" />

Use separate handler, say:

function myOnClickHandler(th){
//say let t=$(th)
}

and in html do this:

<...onclick="myOnClickHandler(this); event.stopPropagation();"...>

Or even :

function myOnClickHandler(e){
  e.stopPropagation();
}

for:

<...onclick="myOnClickHandler(event)"...>

This also works - In the link HTML use onclick with return like this :

<a href="mypage.html" onclick="return confirmClick();">Delete</a>

And then the comfirmClick() function should be like:

function confirmClick() {
	if(confirm("Do you really want to delete this task?")) {
	    return true;
	} else {
	    return false;
	}
};

<div onclick="alert('you clicked the header')" class="header">
  <span onclick="alert('you clicked inside the header'); event.stopPropagation()">
    something inside the header
  </span>
</div>

The best solution would be handle with the event through a javascript function, but in order to use a simple and quick solution using the html element directly, and once that the "event" and "window.event" are deprecated and not universally supported (https://developer.mozilla.org/en-US/docs/Web/API/Window/event), I suggest the following "hard code":

<div onclick="alert('blablabla'); (arguments[0] ? arguments[0].stopPropagation() : false);">...</div>