function validate() {
  
  var errorString = "Please fill in the following fields before submitting:\n\n";
  var isError = false;

  if(document.contactForm.name.value.length == "") {
   isError = true;
   errorString += "Name\n";
  }
  if(document.contactForm.email.value.length == "") {
   isError = true;
   errorString += "Email\n";
  }
  
  if(document.contactForm.email.value.indexOf("@")==-1) {
   isError = true;
   errorString += "Email Address is Invalid.\n";
  }
  if(document.contactForm.phone.value.length == "") {
   isError = true;
   errorString += "Phone\n";
  }

  if(isError) alert(errorString);
  else contactForm.submit();
 }