function setheights() {

if(isNaN(document.getElementById('content_2'))){
document.getElementById('body_content').style.height = document.getElementById('content_2').offsetHeight + 'px';
}

var max = Math.max(document.getElementById('body_left').offsetHeight,document.getElementById('body_content').offsetHeight,document.getElementById('body_right').offsetHeight);

document.getElementById('body_content').style.height = (max) +'px';

document.getElementById('page_footer').style.visibility = 'visible';
}