I know how to do it via using an image, but it needs to be dynamically changing. Are there any tricks to using a color in place of an image? There appears to be very little documentation on using webkit masks.
I'm using this in a Chrome extension that can be used offline (i.e. I can't use PHP for this).
You can use a pseudo element with a colored background like the example at http://www.impressivewebs.com/image-tint-blend-css/