function setHeight(){
var content_main_height = document.getElementById("content_main").offsetHeight;
var content_extra_height = document.getElementById("content_extra").offsetHeight;
if(content_main_height <= content_extra_height){
	document.getElementById("content_center").style.height = 268 + document.getElementById("content_extra").offsetHeight + "px";
} else {
	document.getElementById("content_center").style.height = 268 + document.getElementById("content_main").offsetHeight + "px";
}
}