Email Address Validation 



This is an e-mail address validation function. It allows the usual user@domain syntax, but in addition allows user@[ip] format as well as "User with Spaces"@domain or [ip], all of which are legal syntax, according to W3C. It also checks that the user hasn't done anything silly like having multiple @'s or continuous .'s in the address (e.g. jim@b@c.com and jim@c..b.co.uk).  



<!-- TWO STEPS TO INSTALL EMAIL ADDRESS 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:  Sandeep V. Tamhankar (stamhankar@hotmail.com) -->

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

<!-- Begin
function emailCheck(emailStr) {
// checks if the e-mail address is valid
var emailPat = /^(\".*\"|[A-Za-z]\w*)@(\[\d{1,3}(\.\d{1,3}){3}]|[A-Za-z]\w*(\.[A-Za-z]\w*)+)$/;
var matchArray = emailStr.match(emailPat);
if (matchArray == null) {
alert("Your email address seems incorrect.  Please try again (check the '@' and '.'s in the email address)");
return false;
}
// make sure the IP address domain is valid
var IPArray = matchArray[2].match(/^\[(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})\]$/);
if (IPArray != null) {
for (var i=1;i<=4;i++) {
if (IPArray[i]>255) {
alert("Destination IP address is invalid!")
return false;
      }
   }
}
return true;
}
//  End -->
</script>
</HEAD>

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

<BODY>

<center>
<form name=emailform onSubmit="return emailCheck(this.email.value);">
Your Email Address:  <input type=text name="email"><br>
<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:  1.49 KB -->