[рони]

kulbabka,

function blocksByChildrenTest(){
    var elements = document.getElementById('list-holder').children;
    var maxHeight = 0;
    for(var i = 0; i < elements.length; i++){
      maxHeight = Math.max(elements[i].clientHeight, maxHeight);
    }
    for (i = 0; i < elements.length; i++){
      elements[i].style.height = maxHeight + 'px';
    }
  }