$(document).ready(function() {
    var div1 = $("div#left").height();
    var div2 = $("div#center").height();
    var div3 = $("div#right").height();
	
	var newHeight = div1;
	if(div2 > newHeight) newHeight = div2;
	if(div3 > newHeight) newHeight = div3;
	
    $("div#left").height(newHeight);
    $("div#center").height(newHeight);
    $("div#right").height(newHeight);
});