function PostForm(nextvar) {
   document.wizardform.action.value="Next";
   if (nextvar) document.wizardform.nextscreen.value=nextvar;
  document.wizardform.submit();
 }
  function PostFormPrev() {
   document.wizardform.action.value="Previous";
  document.wizardform.submit();
 }

  <!-- Begin
  
  function checkrequired(which) {
      var pass=true;
      if (document.images) {
          for (i=0;i<which.length;i++) {
              var tempobj=which.elements[i];
              if (tempobj.name=="Forename" || tempobj.name=="Surname" || tempobj.name=="Company" || tempobj.name=="Telephone" || tempobj.name=="Email" || tempobj.name=="comments") {
                  if (tempobj.value=='') {
                      pass=false;
                      break;
                  }
              }
          }
      }
      
      if (!pass) {
          alert("Please make sure the required field "+tempobj.name+" is filled in.");
          return false;
      }
      else
          return true;
  }
  
  function checkEmail(myForm) {
      if (/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,4})+$/.test(myForm.email.value)){
          return (true);
      }
      alert("Please enter a valid email address!");
      return (false);
  }
  
//  End -->