How can I get the mouse coordinates relative to a parent div? Javascript

The accepted answer didn’t work for me in Chrome. Here’s how I solved it:

function relativeCoords ( event ) {
  var bounds = event.target.getBoundingClientRect();
  var x = event.clientX - bounds.left;
  var y = event.clientY - bounds.top;
  return {x: x, y: y};
}