The Internet Engineering Task Force (IETF) document, RFC 3696, “Application Techniques for Checking and Transformation of Names” by John Klensin, gives several valid e-mail addresses that are rejected ...

You can use PHP's filter functions to filter/validate the form input. Here is a good tutorial to get you started. The email and URL filters aren't great (there was a recent discussion here on that ...

HTML5 offers form field validation support built into the HTML form input tags that should greatly reduce the need for JavaScript validation code. In this post, I look at some examples of this.