Update to the Google & Safari Double Firing mouseup Issue

Yesterday, I wrote about an issue I was having with Google & Safari’s way of handling text selection & the “mouseup” event versus Firefox & IE. I installed Opera 10.51 as well to ensure I tested this on the major browsers and Opera behaved just like Firefox & IE. So this was definitely specific to Chrome & Safari (and I assume Webkit as well).

It was an odd scenario but using a closure I found a workaround. This morning I was happy to see a comment from my friend Diego Perini with an explanation of what he feels is the cause and also an alternative fix.

you have setup an on “mouseup” event so it is normal it fires each time you release the mouse button. You are filtering “mouseup” to act only if a selection exists, that’s ok. Unfortunately the difference between the browsers you mention is that in Firefox the selection is cleared as soon as the next “mousedown” while in Safari/Chrome it is cleared on “mouseup” so when fired your filtering will still find a selection active on Safari/Chrome, thus the second alert you see.

This is how you can alternatively fix that problem, just add these lines:

[code lang=”js”]
function clearSelectedText() {
if (window.getSelection) {
} else if (document.getSelection) {
} else {
var selection = document.selection && document.selection.createRange();
if (selection.text) {

addEvent(document, “mousedown”, clearSelectedText);
Hope this help fix it and explain what happens in Safari/Chrome, I wouldn’t mark this as a bug. Have fun.

This did in fact fix it and I like it much better because it avoids the need to attach a closure to an event, which could lead to a memory leak. Thanks Diego!

While this does provide a great workaround, it still leaves unanswered the reason that Chrome & Safari (and Webkit??) behave differently than IE, Firefox & Safari. I’m not sure if the expected behavior for “mouseup” & “mousedown” when selected text is present is clearly defined in a specification but this is just another example of how lack of consensus causes web developers to jump through hurdles for no clear reason.

Rey Bango


  1. Rey, a couple of times you say “Safari & Chrome (and Webkit?)” … That’s like saying “Firefox & Camino (and Gecko?)”.

    In any case, it is curious why the implementations are different. Is this specified anywhere or is it one of those things that’s left up to the browser vendors?

    • @Andrew: It was meant more like saying any Webkit-based browser but I see your point. :)

      As for it being specified, I’m not sure. I plan on looking into it.

  2. This is a user implementation of functionality that is not natively supported by current browsers. Rey needs a global “selection” event mechanism which is only available on input and textarea elements (on those you could probably use the “select” event).

    For this reason I don’t think there are specifications defining this exact behavior.

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