matchHeight=function(){

         var divs,contDivs,maxHeight,divHeight,d;

         // get all <div> elements in the document

         divs=[document.getElementById('left'),document.getElementById('center'),document.getElementById('right')];

         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
	 
		contDivs[0].style.height=maxHeight+'px';
		contDivs[1].style.height=maxHeight+'px';
	
    }

    // execute function when page loads

    window.onload=function(){
             matchHeight();

}