function sElement( obj1, obj2 )
{
	document.getElementById( obj1 ).style.display = 'block';
	document.getElementById( obj2 ).style.display = 'none';
}

function validate_required(field, txt)
{
	with (field)
  	{
  		if (value==null||value=="")
  		{
		    alert(txt);
	    	return false;
  		}
	  	else
			return true;
    }
}