function checkform ( preview )
{
  var stripped = preview.Phone.value.replace(/[\(\)\.\-\ ]/g, ''); 
  var emailRegex = /^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$/;
  
  //declare valid variable with all valid characters: digits from 0 to 9 and backslash
         var valid = "0123456789/";
    //declare variable for counting number of slashes
         var slashcount = 0;
		 
  // generic
  if (preview.FullName.value == "") {
    alert( "Please enter your Full Name." );
    preview.FullName.focus();
    return false ;
  }
  if (preview.ChildsName.value == "") {
    alert( "Please enter your Child's Name." );
    preview.ChildsName.focus();
    return false ;
  }
  
  if (preview.formmail_mail_email.value == "") {
    alert( "Please enter your email address." );
    preview.formmail_mail_email.focus();
    return false ;
  } else if(!preview.formmail_mail_email.value.match(emailRegex)) {
    alert( "You have entered an invalid email." );
	preview.formmail_mail_email.focus();
    return false;
  }
  if (preview.Phone.value == "") {
    alert( "Please enter your phone number." );
    preview.Phone.focus();
    return false ;
  } else if (isNaN(parseInt(stripped))) {
     alert( "The phone number contains illegal characters." );
     preview.Phone.focus();
     return false ;
    } else if (!(stripped.length == 10)) {
        alert( "The phone number is the wrong length. Make sure you included an area code." );
		preview.Phone.focus();
		return false ;
	}
  if (preview.session.value == "") {
    alert( "Please chose a preferred session date." );
    preview.session.focus();
    return false ;
  }
  if (preview.alternate.value == "Select a date...") {
    alert( "Please chose an alternate session date." );
    preview.alternate.focus();
    return false ;
  }
	
  return true ;
  
}