function checkForm(check_array){
  for (var i in check_array){
    if (document.forms[0].elements[i].value==""){
      alert ("Please fill in the '"+ check_array[i]  + "' field before clicking 'Submit'");
      return false;
    }
  }
  if (document.forms[0].disclaimer.checked==false){
    alert ("Please read and agree to the disclaimer at the end of the form before clicking 'Submit'");
    return false;
  }
}