jQuery $(el).overlaps(otherEl) helper

overlaps.jquery.coffee

$.fn.overlaps = (el) ->
  el = $(el)

  o =
    el1: @offset()
    el2: el.offset()

  el1 =
    x1: o.el1.left
    x2: o.el1.left + @width()
    y1: o.el1.top
    y2: o.el1.top + @height()

  el2 =
    x1: o.el2.left
    x2: o.el2.left + el.width()
    y1: o.el2.top
    y2: o.el2.top + el.height()

  (el1.x1 < el2.x2) and (el1.x2 > el2.x1) and (el1.y1 < el2.y2) and (el1.y2 > el2.y1)

overlaps.jquery.js

$.fn.overlaps = function(el) {
  var el1, el2, o;
  el = $(el);
  o = {
    el1: this.offset(),
    el2: el.offset()
  };
  el1 = {
    x1: o.el1.left,
    x2: o.el1.left + this.width(),
    y1: o.el1.top,
    y2: o.el1.top + this.height()
  };
  el2 = {
    x1: o.el2.left,
    x2: o.el2.left + el.width(),
    y1: o.el2.top,
    y2: o.el2.top + el.height()
  };
  return (el1.x1 < el2.x2) && (el1.x2 > el2.x1) && (el1.y1 < el2.y2) && (el1.y2 > el2.y1);
};