 Zip Code Validation 



Ensure that your visitors enter a properly formatted 5 digit, or 5 digit+4 zip code. The visitor is alerted if any information is invalid and asked to try again. Cool! 
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<!-- TWO STEPS TO INSTALL ZIP CODE VALIDATION:

  1.  Copy the coding into the HEAD of your HTML document
  2.  Add the last code into the BODY of your HTML document  -->

<!-- STEP ONE: Paste this code into the HEAD of your HTML document  -->

<HEAD>

<SCRIPT LANGUAGE="JavaScript">
<!-- Original:  Brian Swalwell -->

<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! http://javascript.internet.com -->

<!-- Begin
function validateZIP(field) {
var valid = "0123456789-";
var hyphencount = 0;

if (field.length!=5 && field.length!=10) {
alert("Please enter your 5 digit or 5 digit+4 zip code.");
return false;
}
for (var i=0; i < field.length; i++) {
temp = "" + field.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.length==10) && ""+field.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;
}
//  End -->
</script>
</HEAD>

<!-- STEP TWO: Copy this code into the BODY of your HTML document  -->

<BODY>

<center>
<form name=zip onSubmit="return validateZIP(this.zip.value)">
Zip: <input type=text size=30 name=zip>
<input type=submit value="Submit">
</form>
</center>

<p><center>
<font face="arial, helvetica" size="-2">Free JavaScripts provided<br>
by <a href="http://javascriptsource.com">The JavaScript Source</a></font>
</center><p>

<!-- Script Size:  1.39 KB -->