Handling click events on z-index'd layers

StackOverflow https://stackoverflow.com/questions/1026060

Question

I have 2 z-index layers in a map application I'm building. I have a problem when I click on the layers to zoom in. The click handler is on the underlying z-index layer and I don't want it to fire when a control in the overlying layer is clicked.

The problem i have is that the event gets raised no matter what but the originalTarget property of the event is not the image in the underlying layer when something on the top layer is clicked. Is there anyway to change this?

Was it helpful?

Solution

It's called event-bubbling, and you can control it with the event.stopPropagation() method (event.cancelBubble() in IE). You can also control it by returning true/false from handlers called by onwhatever attributes on elements. It's a tricky subject so I suggest you do some research.

Info: cancelBubble, stopPropagation

OTHER TIPS

Although this does not address the problem directly it may be a viable workaround until a more fitting solution presents itself.

Write a single function to be called onClick and allow the function enough smarts to know who called it. The function then takes the appropriate action based upon who clicked it. You could send it pretty much anything that would be unique and then use a switch.

simplified example :

<html>
<body>

<script type="text/javascript">
function myClickHandle(anID)
{
switch(anID){
case 'bottom': 
      alert("I am on the bottom");
      break;
case 'top':
      alert("I am on the top");
      break;
}
}
</script>

<html>
<div style="z-index:10"><input type=button value='top' onclick="myClickHandle(this.value)"/></div>
<div style="z-index:11"><input type=button value='bottom' onclick="myClickHandle(this.value)"/></div>
</body>
</html>

I think the best practice is to detach the event handler when the control moves to the upper layer and when the control gets back to the lower layer, you can reattach the events.

priority to the element who has the great z-index

http://api.jquery.com/event.stopPropagation/

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