<script language="javascript">
    matchHeight=function(){
         var divs,contDivs,maxHeight,divHeight,d;
         // get all <div> elements in the document
         divs=document.getElementsByTagName('div');
         contDivs=[];
         // initialize maximum height value
         maxHeight=0;
         // iterate over all <div> elements in the document
         for(var i=0;i<divs.length;i++){
              // make collection with <div> elements with class attribute 'container'
              if(/\bcontainer\b/.test(divs[i].className)){
                    d=divs[i];
                    contDivs[contDivs.length]=d;
                    // determine height for <div> element
                    if(d.offsetHeight){
                         divHeight=d.offsetHeight;
                    }
                    else if(d.style.pixelHeight){
                         divHeight=d.style.pixelHeight;
                    }
                    // calculate maximum height
                    maxHeight=Math.max(maxHeight,divHeight);
              }
         }
         // assign maximum height value to all of container <div> elements
         for(var i=0;i<contDivs.length;i++){
              contDivs[i].style.height=maxHeight;
         }
    }
    // execute function when page loads
    window.onload=function(){
         if(document.getElementsByTagName){
              matchHeight();
         }
    }
    </script>