function align_height(els){
	var i, l = els.length, max = 0, doms = [];
	for(i = 0; i < l; i++){
	  doms[i] = document.getElementById(els[i]);
	  if(doms[i] && doms[i].offsetHeight > max){
	    max = doms[i].offsetHeight;
	  }
	}
	for(i = 0; i < l; i++){
	  if(doms[i]){
	    doms[i].style.height = max + 'px';
	  }
	}
}