Place background image 1em from the right?

Question

As far as I can tell, it is not possible to place a CSS background image 1em from the right border of any block, neither is it possible to place a image 1em from the bottom.

Answer 1

After some research the actual x pixel length of the background position is always counted from the left side of the element. The only way to make this work (without using other elements) would be to use javascript, calculate the left length given the elements width:

var rightMargin = "10"; // in pixels
var imageWidth = "16";
var left = element.style.clientWidth - imageWidth - rightMargin;

element.style.backgroundPosition = "0px " + left + "px";