function correct_layout () {
  if(document.getElementById('main_col2').offsetHeight) {

    var div_heights = new Array(
		
      document.getElementById('main_col2').offsetHeight,
      document.getElementById('main_col1').offsetHeight,
      document.getElementById('main_col3').offsetHeight

    );
     

    div_heights = div_heights.reverse(div_heights.sort(num_sort));
    var style_height = div_heights[0] + "px";	
    document.getElementById('main_col1').style.height = style_height;
    document.getElementById('main_col2').style.height = style_height;
    document.getElementById('main_col3').style.height = style_height;
  }
}
function num_sort(a,b) {
	 return a-b;
}