function Validate()
{
    var themessage = "You are required to complete the following fields: ";
    var allgood = true;

    if (document.contactpage.name.value=="") {
      themessage = themessage + " - name";
      allgood=false;
    }
    
     if (document.contactpage.email.value=="") {
      themessage = themessage + " - email address";
      allgood=false;
    }
     if (document.contactpage.number.value=="") {
      themessage = themessage + " - tel";
      allgood=false;
    }
     if (document.contactpage.message.value=="") {
      themessage = themessage + " - message";
      allgood=false;
    }
   
    // and so on and so forth for each field

    //alert if fields are empty and cancel form submit
    if (!allgood)
         alert(themessage);


    return allgood;

}