Все нашел, если кому надо:
function overlap($div1, $div2) {
var x1 = $div1.offset().left,
y1 = $div1.offset().top,
height1 = $div1.outerHeight(true),
width1 = $div1.outerWidth(true),
b1 = y1 + height1,
r1 = x1 + width1,
x2 = $div2.offset().left,
y2 = $div2.offset().top,
height2 = $div2.outerHeight(true),
width2 = $div2.outerWidth(true),
b2 = y2 + height2,
r2 = x2 + width2;
if (b1 < y2 || y1 > b2 || r1 < x2 || x1 > r2) return false;
return true;
}