function getLongest() {
 	colLength = new Array(2);
 	colLength[0] = document.getElementById("content").offsetHeight;
 	colLength[1] = document.getElementById("right_sidebar").offsetHeight;
 	colLength[2] = document.getElementById("left_id").offsetHeight+100;
	colLength.sort();
	colLength.reverse();
 	return colLength[0];
}

function setheight()
{ 
var heightw=getLongest();
if (heightw>1500) 
{ heightw=heightw+50;
 document.getElementById('content').style.height=heightw-100+"px";
 document.getElementById('right_sidebar').style.height=heightw-100+"px";
 document.getElementById('left_id').style.height=heightw+"px";
 document.getElementById('footer').style.top=heightw+500+"px";
}
else
{
document.getElementById('content').style.height="1200px";
 document.getElementById('right_sidebar').style.height="1200px";
 document.getElementById('left_id').style.height="1020px";
document.getElementById('footer').style.top = "1600px";
}
}