function fixColumns() {
  var main = $('main');
  var left = $('left');
  var right = $('right');
  
  if (main) {
    height = main.offsetHeight;
    var mainExtras = main.getStyle('padding-top').toInt()
                    + main.getStyle('padding-bottom').toInt()
                    + main.getStyle('border-top').toInt()
                    + main.getStyle('border-bottom').toInt();
  }
  if (left) {
    if (left.offsetHeight > height) height = left.offsetHeight;
    var leftExtras = left.getStyle('padding-top').toInt()
                    + left.getStyle('padding-bottom').toInt()
                    + left.getStyle('border-top').toInt()
                    + left.getStyle('border-bottom').toInt();
  }
  if (right) {
    if (right.offsetHeight > height) height = right.offsetHeight;
    var rightExtras = right.getStyle('padding-top').toInt()
                    + right.getStyle('padding-bottom').toInt()
                    + right.getStyle('border-top').toInt()
                    + right.getStyle('border-bottom').toInt();
  }
  if (right) right.setStyle('min-height', height - rightExtras);
  if (left) left.setStyle('min-height', height - leftExtras);
  if (main) main.setStyle('min-height', height - mainExtras);

}

window.addEvent('load', function() {
  fixColumns();
});