function validate_required(field,alerttxt)
      {
      with (field)
      {
      if (value==null||value=="")
        {alert(alerttxt);
		return false;}
      else {return true}
      }
      }
	  
	  function validate_required_select(field,alerttxt)
      {
        with (field)
        {
        if (selectedIndex==-1 || selectedIndex==0)
          {alert(alerttxt);
		  return false;}
        else {return true}
        }
      }
	  
	  function validate_email(field,alerttxt)
      {
        with (field)
        {
        apos=value.indexOf("@");
        dotpos=value.lastIndexOf(".");
        if (apos<1||dotpos-apos<2) 
          {alert(alerttxt);return false;}
        else {return true;}
        }
      }