window.onload = initAll;

function initAll(){
               
            var panelLeftHight = document.getElementById('mainPanelLeft').offsetHeight;
            var panleRightHight = document.getElementById('mainPanelRight').offsetHeight;
            if(panelLeftHight <panleRightHight ){
                    document.getElementById('mainPanelLeft').style.height = panleRightHight+"px";
            }
            if(panelLeftHight >panleRightHight ){
                    document.getElementById('mainPanelRight').style.height = panelLeftHight+"px";
            }
   
}