How to force ie8 to repaint after adding a class to a dom element

Question

In ie8 if elements don\'t \'repaint\' with the associated css when you change the classname, how can you force the browser to refresh and not kill ie8 performance?

This

Answer 1

Fire a move or resize event on it.

var ie8 = whateverYouUseToDetectIE();
var element = document.getElementById("my-element");
element.className += " new-class";
if (ie8) {
    element.fireEvent("resize");
}

Answer 2

The correct answer to this question is that you need to actually change the content rule.

.black-element:before { content:"Hey!"; color: #000;}
.red-element:before { content:"Hey! "; color: #f00;}

Notice the extra space I added after Hey! on .red-element

Answer 3

Ridiculously, this works:

function ie8Repaint(element) {
    element.html(element.html().replace('>', '>'));
}

Nothing actually changes in the DOM so it won't affect any other browsers.

Answer 4

I had a lot of difficulty and tried everything to no avail...until I tried this for IE8

function toggleCheck(name) {
  el = document.getElementById(name);
  if( hasClass(el, 'checked') ) {
    el.className = el.className.replace(/checked/,'unchecked');
  } else if( hasClass(el, 'unchecked') ) {
    el.className = el.className.replace(/unchecked/,'checked');
  }
  document.body.className = document.body.className;
}
function hasClass(element, cls) {
  return (' ' + element.className + ' ').indexOf(' ' + cls + ' ') > -1;
}

And now my CSS changes for my checkboxes work beautifully for IE8, Chrome, and Firefox!

Answer 5

This expands on the other answers here. You need to both add a new class (Doug's answer) and ensure the class has a different content value (Adam's answer). Changing the class alone may not be enough. The content change is needed to force IE8 to repaint. Here is a related blog post.

Here is the JQuery to change add the new class:

$(".my-css-class").addClass("my-css-class2");

Here is CSS with the 2nd class having a slightly different content value:

.my-css-class:before {content: "\e014";}
.my-css-class2:before {content: "\e014 ";}

Answer 6

The solution I came up with for my ie8 issue was to add/remove a class on a near parent of the element i'm changing. Since I'm using modernizer, I check for ie8 and then do this add/remove dance to get the new css to paint.

        $uicontext.addClass('new-ui-look');
        if ($('html').is('.ie8')) {
            // IE8: ui does not repaint when css class changes
            $uicontext.parents('li').addClass('z').removeClass('z');
        }