Dynamically setting background-color on :hover state
by Schepp
HTML
<div id="element">Text</div>
CSS
div {
background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAAE0lEQVR4XgXAAQ0AAABAMP1L38IF/gL+/AQ1bQAAAABJRU5ErkJggg==);
background-color: transparent;
}
div:hover {
background-image: none;
background-color: inherit;
}
JavaScript
document.getElementById('element').style.backgroundColor = 'red';