function boxes_height()
{
  if(document.getElementById('m1') && document.getElementById('m2'))
  {
	  if(document.getElementById('m2').clientHeight>document.getElementById('m1').clientHeight)
	  {
	    y = document.getElementById('m2').clientHeight;
	    document.getElementById('m1').style.height = y + 'px';
	  }
	  else
	  {
	    y = document.getElementById('m1').clientHeight;
	    document.getElementById('m2').style.height = y + 'px';
	  }
	  document.getElementById('m1').style.visibility = 'visible';
	  document.getElementById('m2').style.visibility = 'visible';
  }
  
  else if(document.getElementById('m2'))
	document.getElementById('m2').style.visibility = 'visible';
  else if(document.getElementById('m1'))
	document.getElementById('m1').style.visibility = 'visible';
}