Safari 5.1 broke HTML native drag and drop?

问题:

Last night, I thought I'd do a quick project to demonstrate HTML5 capabilities and to try some things out. However, I can't seem to figure out how to get drag and drop to work in Safari, while it works perfectly in Chrome and Firefox. More precisely, it seems that drop event does not fire in Safari, when you try to drag an image inside the website into the drop area. At the same time it does fire when you drag and drop a file from desktop.

I'm not really sure, but I'm pretty certain that when I tried the same script at work (where I have Safari 5.0.2 etc), it fired the drop event (going to check it tomorrow to be sure) and gave me the FileReader-related errors that were expected. But when I just installed Safari 5.1 on my own PC, I only get dragover, enter and leave events (and drop too if the file was dragged into the browser).

I've been Googling for some time now and don't seem to find a single example of drag and drop that actually works in Safari 5.1. Even Safari's dev-centre's sample doesn't work, let alone html5demo.com 1 and html5demo.com 2. This leads me to think whether the Safari has a bug, or maybe they have implemented something mandatory that isn't reflected in the dev-centre (last updated in 2009).

The script I'm trying to fix is at my site (sorry guys, no problem specific code to post, as it seems to be broken elsewhere too).

PS! I might have introduced some bugs into my own site while desperately trying to fix the drag and drop in Safari, but I'm too tired to fix them right now.

UPDATE: Just confirmed at work that the drop event does fire in Safari 5.0.2 on Mac OS X.

UPDATE 2: Also confirmed that everything works perfectly fine with Safari 5.0.6 on Win 7, the same computer that fails with 5.1

回答1:

Testing with Safari 5.1.7 Mac:

To see the drop event fire, you have to handle the dragover event and call event.preventDefault().

Here's the (quite entertaining) discussion where I found the answer:

http://www.quirksmode.org/blog/archives/2009/09/the_html5_drag.html

I don't know if this really solves the question because the asker's site (at least as of today) does this. It works fine on my machine (as do the HTML5 demo pages). But this may help someone coming to this thread with this problem who doesn't know about this rather unintuitive implementation detail.

回答2:

I am using Safari 5.1.5 (7534.55.3) on a Windows 7 PC which I just installed the other day, no previous installs of Safari and I cannot get any of the online HTML5 drag-n-drop demos to work.

I am working on a project with drag-n-drop and Modernizr tells me that I'm good to go with Safari (Modernizr.draganddrop == true), but when I actually drop the item the drop event does not fire.

I've added alert debugging and nothing.

My testing shows that Safari 5.1.5 (7534.55.3) on a Windows 7 PC drop event is broken. All other drag events seem to work: dragstart, dragend, dragenter, dragleave, dragover.

回答3:

Just to clarify: Visited your site and found no errors. Opened the console, no error, and everything appeared to function as designed. Tried all provided examples with no error.

All examples work fine Safari Version 5.1 (7534.48.3). Sorry, mate – Maybe it's a setting you've changed?

Allow me to suggest a possibility:

Go to Safari->Empty Cache... Then Safari->Reset Safari... Try reloading the page.

Likely, there's something cached that's creating a conflict. There seems to be nothing wrong with your script in the slightest.

Edit

Some things to check...

Are any of your function names containing reserved words? I've done this, had it not throw any errors, but it simply wouldn't work.

I've had some weird issues with Safari not running methods written as funcName = function(){}. If you can pin down the method that isn't firing (I add a little function when I'm developing called DBG which I'll add below – basically, if a debug flag is set, you log to the console), you can try rewriting the function.

// Some sort of boolean flag.
var debug = true;

// This is kind of an obvious function, but can be expanded as you like.
// Little tricks to make life easier.
function DBG(str) {
  debug ? console.log(str) : return;
}

I still think ultimately this boils down to something caching wrong, but it's worth a try.

回答4:

I encountered similar issues, the drop event appeared to not be firing. Safari apparently expects the "dragover" event to also be bound. As soon as I also added that, it worked. So ... I'm sharing in case it's relevant.

My first attempt:

$(document).bind 
  drop: (e) ->
    // This never gets fired in safari (does work in chrome)
    console.log e.originalEvent.dataTransfer.files
    false

My "fix":

$(document).bind 
  dragover: (e) ->
    console.log e
    false
  drop: (e) ->
    // This does get fired (in chrome and safari)
    console.log e.originalEvent.dataTransfer.files
    false