function CheckZipSilent(field) {
  if (field.value.length!=5 && field.value.length!=10) {
    return false;
  }
  var valid = "0123456789-";
  var hyphencount = 0;
  for (var i=0; i < field.value.length; i++) {
    temp = "" + field.value.substring(i, i+1);
    if (temp == "-") hyphencount++;
    if (valid.indexOf(temp) == "-1") {
      return false;
    }
    if ((hyphencount > 1) || ((field.value.length==10) && ""+field.value.charAt(5)!="-")) {
      return false;
    }
  }
  return true;
}

function CheckZip(field) {
  if (field.value.length!=5 && field.value.length!=10) {
    alert("Please enter your 5 digit or ( 5 + 4 ) digit  ZIP  code.");
    return false;
  }
  var valid = "0123456789-";
  var hyphencount = 0;
  for (var i=0; i < field.value.length; i++) {
    temp = "" + field.value.substring(i, i+1);
    if (temp == "-") hyphencount++;
    if (valid.indexOf(temp) == "-1") {
      alert("Invalid characters in your ZIP code.  Please try again.");
      return false;
    }
    if ((hyphencount > 1) || ((field.value.length==10) && ""+field.value.charAt(5)!="-")) {
      alert("The hyphen character should be used with a properly formatted 5 digit+four  ZIP  code, like '12345-6789'.   Please try again.");
      return false;
    }
  }
  return true;
}