Canceling event bubbling and default action in Internet Explorer

[Kurt]

Hi all!

Please look at the following code:

if (window.event) {
window.event.cancelBubble = true;
window.event.returnValue = false;
return false;
}

Question: Is the last statement (return false) really needed in canceling event bubbling and default action in IE??

Thanks in advance for any help

Kurt

[NakedIntruder]

I don't think it's needed, here's the one I use if it helps you mate;

/* Stop events being fired in parents (will stop links opening after an onClick)
----------------------------------------------------------------------- */
function noBubble(e) {
if(window.event){window.event.cancelBubble=true;window.event.returnValue=false}if(e&&e.stopPropagation&&e.preventDefault){e.stopPropagation();e.preventDefault()}
}

[Kurt]

Hello NakedIntruder,

thanks for your prompt help!

Kurt

ps. the code is from sitepoints-book "dhtml javascript and dom" by langridge. my personal experience was that I dont need the last line, but its good to have the confirmation of an javascript-expert (I am a hobby-developer only)

[dmitriy]

window.event.returnValue = false; - dom method of canceling bubble

[NakedIntruder]

ps. the code is from sitepoints-book "dhtml javascript and dom" by langridge. my personal experience was that I dont need the last line, but its good to have the confirmation of an javascript-expert (I am a hobby-developer only)

I got it from there too hehe, I'm no expert though so don't rely on what I'm currently using!

[JVLB]

cancelBubble and returnValue, both IE-only methods of the event object, are different in function. cancelBubble prevents an event from propagating up the container chain of element objects. This means that the event still registers on the target object, say a span contained within a div, within the body, etc. If cancelBubble is invoked, the event doesn't bubble up past the span. If cancelBubble is not invoked, the event is passed up the chain, step by step, until the document or window container, depending on the particular browser. Setting returnValue = false; however, means that even the target object essentially ignores the event.

The DOM methods that correspond are stopPropagation and preventDefault.

Note: Edited per Kurt's accurate observation, below.

[Kurt]

cancelBubble and returnValue, both IE-only methods of the event object, are different in function. cancelBubble prevents an event from propagating up the container chain of element objects. This means that the event still registers on the target object, say a span contained within a div, within the body, etc. If cancelBubble is invoked, the event doesn't bubble up past the span. If cancelBubble is invoked, the event is passed up the chain, step by step, until the document or window container, depending on the particular browser. Setting returnValue = false; however, means that even the target object essentially ignores the event.

JVLB,

Thanks for explaining the difference between cancleBubble and returnValue

Regards

Kurt

BTW: When I understood you right , there is a small typo in the statement and it should say:

If cancelBubble is not invoked, the event is passed up the chain, step by step, until the document or window container, depending on the particular browser.