Question

I’m using the following code to make sure fields are filled in. How can I add some code to make sure it’s a valid email?

function verify() {
if ($("#ddlBusinessName").val() == "0") {
            alert("Please select the name.");
        }
        else if ($("#txtEmail").val().length <= 0 || $("#txtEmailConfirm").val().length <= 0) {
            alert("Please enter the email address and confirm the email address.");
             else if ($("#TxtPassword").val().length <=0 || $("#TxtConfirmPassword").val().length <=0) {
            alert("Please enter your password.");
        }

         }

EDIT
How can I implement this into my code though?

 function validateEmail(email) { 
var re = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\
".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA
-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
return re.test(email);
} 

Answer 1

The only safe way to validate an email address is actually sending an email to it. If this fails with a (permanent – graylisting errors would be temporary) error code you know the address is invalid.

Of course you cannot do that in JavaScript – so I’d limit the client-side check to a very simple check – something like /^[^@ ]+@[^@ ]+\.[^@ ]+$/ (thx @NedBatchelder) would do the job.