Ctrl or Shift effects on the `onclick` event of an anchor tag in each browser

Question

I recently discovered that different browsers handle the onclick event differently when the Control or Shift keys are pressed. They diverge similarly on behavior for for following links by clicking the middle mouse button.

With the following link:

<a href="http://www.example.com/" onclick="alert('onclick');">go to example.com</a>

Onclick browser support table

Mouse    Keyboard       Chrome    Firefox   Safari    Opera     IE5.5     IE6       IE7       IE8       IE9       

Left     None           yes       yes       yes       yes       yes       yes       yes       yes       yes
Left     Ctrl           yes       yes       yes       yes       ?         yes       no        no        ?
Left     Shift          yes       yes       yes       yes       ?         yes       yes       yes       ?
Middle   None           yes       no        yes       no        ?         N/A       no        no        ?

Can someone please fill in the question marks for me? Also; I'm wondering if the behaviour differs for each version of Chrome, Firefox, Safari and Opera.

Finding a logical pattern in this behavior would be even nicer, but I don't think there is one, unfortunately. :)

Granivorous

Answer 1

See my answer to a related question.

This is due to the "expected behaviour" when a user uses click-modifier keyboard buttons - the user expects Ctrl+Click on a link to open that link in a new tab or window. The chaps at Microsoft decided that the only reason a user would Ctrl+click because they were expecting that behaviour, thus, such clicks do not fire the onclick event in Internet Explorer.

Outdoors

BTW: I don't have the intention to change the behaviour of web browsers. I just need to measure commercial clicks (via some JavaScript library). I got this working for IE7 & IE8 via an event handler. But I'm curious about IE5.5 and IE9's behaviour. Also; since tabbed browsing is getting more and more popular (also via right clicks). So some day we'll have to switch to a redirect method. – Granivorous

There they go again... thinking they know more about what the user expects than the actual developer of the application. – Clie