Question

I am currently trying to animate two div elements in a carousel-type container. Here is the markup as it appears in the DOM:

<div id="transitioner" style="width: 2880px; height: 775px; left: -1440px; ">
    <div id="view1" class="view active" style="width: 1440px; height: 775px; ">
        <header>
            <h1>This is page 1</h1>
        </header>
        <article style="height: 699px; ">
            <p>Tap me anywhere to go to the next view</p>
        </article>
        <footer>
            <p>This is my footer</p>
        </footer>    
    </div>
    <div id="view2" class="view" style="width: 1440px; height: 775px; ">
        <header style="">
            <h1>This is page 2</h1>
        </header>
    </div>
</div>

And here is the CSS for the #transitioner element:

#transitioner {
    position: absolute;
    top: 0;
    -webkit-transition: all 0.2s ease-in-out;
}

Finally, the JS:

function GotoView(view)
{
    var roller = $('<div id="transitioner" />');
    roller.width((viewport.width * 2)).height(viewport.height);
    var current = $('.view.active').clone(true, true);
    $('.view.active').remove();
    current.prependTo(roller);

    var new_view = view.clone(true, true);
    view.remove();
    new_view.appendTo(roller);

    roller.appendTo($('body'));
    $('body').addClass('transitioning');
    //window.setTimeout(function() { roller.css({ left: 0 - viewport.width }) }, 2000);
    roller.css({ left: 0 - viewport.width });
}

I update the left position of the containing div (i.e. #transitioner), but unless I put in a setTimeout, the CSS transition does not execute, rather the containing div simply ‘jumps’ to the desired new left offset.

I have put together a jsFiddle so you can see the symptoms > http://jsfiddle.net/XPUPQ/

My question is: what is this happening, and short of using the JS setTimeout() is there any way to circumvent this?

Answer 1

You need to trigger a browser reflow

http://jsfiddle.net/XPUPQ/1/

You could do that with $("body")[0].offsetWidth; for example.

This is actually a legit technique that twitter bootstrap uses for example