Add a way to trigger updates from site JS

[jefferyto]

Folks are using this with elements that are styled dynamically with JS (#31, https://github.com/louisremi/background-size-polyfill/issues/15#issuecomment-33117627, https://github.com/louisremi/background-size-polyfill/issues/32#issuecomment-33461611), so we need a way for site scripts to trigger an update after they're done styling.

[jefferyto]

Until this is done, a workaround is to "touch" the element, i.e. assign to any property of the DOM object (it doesn't matter if the property value remains unchanged).

For example, if the elements that use the polyfill all <div class="bg">, then this should cause an update:

$('div.bg').prop('class', 'bg');

[rubensayshi]

$('div.bg').get(0).style.behavior = $('div.bg').get(0).style.behavior;

does the trick

[jefferyto]

Thanks @rubensayshi - as I said, a workaround is to assign any value (even the same value) to any property.

[leup]

:+1: