function S(id){return document.getElementById(id)}
  function xx(a,b){
	  if (S(b).offsetHeight>S(a).offsetHeight){  S(a).style.height=S(b).offsetHeight+"px";
	  }else{S(b).style.height=S(a).offsetHeight+"px";
	  }
	}
  //µ÷ÓÃ
  window.onload=function(){xx('left','right')}