var texttypes = new Array(10);
   var errortypes = new Array(10);

   function initialize() {

      texttypes[0] = document.form1.elements[1];
      texttypes[1] = document.form1.elements[2];
      texttypes[2] = document.form1.elements[3];
      texttypes[3] = document.form1.elements[4];
      texttypes[4] = document.form1.elements[5];

      errortypes[0] = "First name is required.";
      errortypes[1] = "Last name is required.";
      errortypes[2] = "Email is required.";
      errortypes[3] = "Subject is required.";
      errortypes[4] = "Message is required.";

   }   

   function validateform() {

      initialize();

      for (i=0; i < 5; i++)
         if (texttypes[i].value == "") {

            alert(errortypes[i]);
            return false;

         }

      return true;

   }