onload=function(){
/*ids*/
var col1=document.getElementById('izquierda');
var col2=document.getElementById('centro');
var col3=document.getElementById('ganchos');
var col4=document.getElementById('derecha');
var mx=Math.max(col1.offsetHeight,col2.offsetHeight,col3.offsetHeight);
document.getElementById('izquierda').style.height=document.getElementById('derecha').style.height=document.getElementById('centro').style.height=document.getElementById('ganchos').style.height=mx+'px';

}