Javascript SVG detection with CSS fallback.

svg-detection

# Add below script to html head, before css.

<script>
	function supportsSVG(){if(document.createElementNS&&document.createElementNS("http://www.w3.org/2000/svg","svg").createSVGRect){return true}}if(supportsSVG()){document.documentElement.className+=" svg"};
</script>

# Example scss

.svg-bg-image {
	background: url(_media/image.png) no-repeat;
	height: 100px;
	width: 100px;
	.svg & {
		background: url(_media/image.svg) no-repeat;
		background-size: 100px 100px;
	}
}