divs=new Array("left","content","right")
function anpassen()
{
hoehe=0
for(i=0;i<divs.length;i++)
{
if(parseInt(document.getElementById(divs[i]).offsetHeight)>hoehe)
hoehe=parseInt(document.getElementById(divs[i]).offsetHeight)
}

for(i=0;i<divs.length;i++)
{
document.getElementById(divs[i]).style.height=hoehe+"px";

}
}

window.onload=anpassen