Safari pauses all animation on redirect / form submission

Question

I have an animation that triggers when a link is clicked. It is a jQuery animation that enlarges a div then fades out. To ensure speed, at the exact same time that the link is clicked, the redirect is fired off. This has to happen and I cannot put the redirect in the success function of jQuery's animate(). This redirect is done via a form submission. On Chrome, Firefox, and IE it works as expected, the animation plays and if the page loads entirely before the finish of the animation, it redirects but the animation does play.

On Safari (primarily testing on iPad), as soon as the link is clicked, the page seemingly 'freezes' and the animation fails to execute. There are also GIF's that are on the screen at page load, and if I click a link while those GIF's are on screen and animating, they pause as well. I have seen a post that says to set a timeout, apply styling, then submit, but the problem is that although the HTML will apply that CSS style, it still freezes the screen, and they are not dealing with animation, just static CSS styling.

Here is some example code to show the method of how I am accomplishing this (it is not tested just trying to illustrate my point, so there may be missing parts or syntax errors):

var someData = 'foo'; //This value is irrelevant, just there for syntactical consistency.  $("#link").on("click", function() {      var form = $("<form method='POST'></form>");      form.attr("action", "http://someurl.com");      var input = $("<input type='hidden'/>");      input.val(someData);      form.append(input);      $(document.body).append(form);      form.submit();          //Form has been submitted, now run a short animation for the remaining life of the current page      $(this).animate({width: "100px", height: "100px", opacity: "0"}, 150);    });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>  <div id="link" style="width: 100px; height: 100px; background-color: #FFF">Click Me</div>

Essentially, I need to make sure that once the Safari browser begins to load a new page / link, it does not stop updating the current page. This sounds like a problem in Safari from what I have seen, but this issue has also not been run into very commonly across the web as I have seen. There are posts dealing with GIF animations, but this is a CSS style animation.

Thanks for any help!

Answer 1

What I have found is that Safari actually pauses all animations as soon as the pagehide event is fired, whenever the browser begins loading a new page.

After pagehide, it won't even allow CSS changes such as showing a spinner that was previously hidden.

In order to show the spinner before the pagehide event fires, I needed to add listeners for a[href] clicks and ajaxComplete events.

My guess is that Safari does this to enhance performamce by focusing all available CPU and GPU power to the rendering of the next page.

I think this is a bit extreme, and unfortunate for UX where in many mobile web applications we use spinner animations at page unload to show the user something is happening during the few seconds while a new page is being fetched.

I have so far not found a way to preserve motion animation during page unload; at best the spinner appears frozen but still shows up... a possible workaround is to use a static message to indicate it's "Loading..."

Answer 2

You could use a setTimeout to go to the link after the animation.

var someData = 'foo'; //This value is irrelevant, just there for syntactical consistency.  $("#link").on("click", function() {     setTimeout(doThisAfterTimeExpires,2000);     $(this).animate({width: "100px", height: "100px", opacity: "0"}, 150); });  function doThisAfterTimeExpires(){      var form = $("<form method='POST'></form>");     form.attr("action", "http://someurl.com");     var input = $("<input type='hidden'/>");     input.val(someData);     form.append(input);     $(document.body).append(form);     form.submit();  }