/*
   The isEmpty and isWhitespace functions were taken straight from Netscape's JavaScript development site, http://developer.netscape.com.
*/


      // whitespace characters
      var whitespace = " \t\n\r";

      /****************************************************************/

      // Check whether string s is empty.
      function isEmpty(s)
      { return ((s == null) || (s.length == 0)) }

      /****************************************************************/

      function isWhitespace (s)
      {
           var i;

           // Is s empty?
           if (isEmpty(s)) return true;

           // Search through string's characters one by one
           // until we find a non-whitespace character.
           // When we do, return false; if we don't, return true.

           for (i = 0; i < s.length; i++)
           {
                // Check that current character isn't whitespace.
                var c = s.charAt(i);

                if (whitespace.indexOf(c) == -1) return false;
           }

           // All characters are whitespace.
           return true;
      }

      /****************************************************************/

      function ForceEntry(val, str) {
           var strInput = new String(val.value);

           if (isWhitespace(strInput)) {
                alert(str);
                return false;
           } else
                return true;

      }

      /****************************************************************/

      function ValidateRanking() {
           // This function ensures document.forms[0].nRanking.value >=1 && <= 10

           if (parseInt(document.forms[0].nRanking.value) >= 1 && parseInt(document.forms[0].nRanking.value) <=10)
                return true;
           else
                return false;
      }

      /****************************************************************/

      function ValidateData() {
           var CanSubmit = false;

           // Check to make sure that the full name field is not empty.
           CanSubmit = ForceEntry(document.forms[0].totaladdtapes,"Please select the number of DVDs you want.");
           if(CanSubmit) CanSubmit = ForceEntry(document.forms[0].name, "Please enter your name.");
           if(CanSubmit) CanSubmit = ForceEntry(document.forms[0].street, "Please enter a street address.");
           if(CanSubmit) CanSubmit = ForceEntry(document.forms[0].city, "Please enter a city.");
           if(CanSubmit) CanSubmit = ForceEntry(document.forms[0].state, "Please enter a state.");
           if(CanSubmit) CanSubmit = ForceEntry(document.forms[0].zip, "Please enter a zip code.");
           if(CanSubmit) CanSubmit = ForceEntry(document.forms[0].phonearea, "Please enter a phone number.");
           if(CanSubmit) CanSubmit = ForceEntry(document.forms[0].phoneprefix, "Please enter a phone number.");
           if(CanSubmit) CanSubmit = ForceEntry(document.forms[0].phonesuffix, "Please enter a phone number.");
           if(CanSubmit) CanSubmit = ForceEntry(document.forms[0].email, "Please enter an email address.");
           return CanSubmit;
      }