function eqHeight(e1, e2) {
//get height of e1
if(!e1.parentNode && typeof e1 == 'string') {
e1 = document.getElementById(e1);
var e1_height = e1.offsetHeight;
} else if(typeof e1.offsetHeight != 'undefined') {
//can be 0 too
var e1_height = e1.offsetHeight;
} else throw "unexpected argument(0) in eqHeight, element or element-id expected";

//same on e2
if(!e2.parentNode && typeof e2 == 'string') {
e2 = document.getElementById(e2);
var e2_height = e2.offsetHeight;
} else if(typeof e2.offsetHeight != 'undefined') {
//can be 0 too
var e2_height = e2.offsetHeight;
} else throw "unexpected argument(1) in eqHeight, element or element-id expected";

if(e1_height >= e2_height) {
e2.style.height = e1_height + 'px';
} else {
e1.style.height = e2_height + 'px';
}
}