How can I force WebKit to redraw/repaint to propagate style changes?

Question

I have some trivial JavaScript to effect a style change:

sel = document.getElementById(\'my_id\');
sel.className = sel.className.replace(/item-[1-9]-selected         


        

Answer 1

I was suffering the same issue. danorton's 'toggling display' fix did work for me when added to the step function of my animation but I was concerned about performance and I looked for other options.

In my circumstance the element which wasn't repainting was within an absolutely position element which did not, at the time, have a z-index. Adding a z-index to this element changed the behaviour of Chrome and repaints happened as expected -> animations became smooth.

I doubt that this is a panacea, I imagine it depends why Chrome has chosen not to redraw the element but I'm posting this specific solution here in the help it hopes someone.

Cheers, Rob

tl;dr >> Try adding a z-index to the element or a parent thereof.

Answer 2

Not that this question needs another answer, but I found simply changing the color by a single bit forced a repaint in my particular situation.

//Assuming black is the starting color, we tweak it by a single bit
elem.style.color = '#000001';

//Change back to black
setTimeout(function() {
    elem.style.color = '#000000';
}, 0);

The setTimeout proved critical to move the second style change outside the current event loop.

Answer 3

I've found this method to be useful when working with transitions

$element[0].style.display = 'table'; 
$element[0].offsetWidth; // force reflow
$element.one($.support.transition.end, function () { 
    $element[0].style.display = 'block'; 
});