特定域的Java电子邮件验证

Question

I can't figure out what is missing so that when e-mail is valid it will skip the last invalid message and move to next item on form for validation:

enter code here 
    if (document.form1.email.value.length > 0) {

    var tst = document.form1.email.value;
    var okd = ['bankofamerica.com','baml.com','magner.com','ml.com','ust.com','ustrust.com']
    for (var i = 0; i < okd.length; i++) { okd[i] == okd[i].toLowerCase() }

    var emailRE = /^[a-zA-Z0-9._+-]+@([a-zA-Z0-9.-]+\.[a-zA-Z]{2,4})$/
    var aLst = emailRE.exec(tst)
    if (!aLst) {
        alert(tst + ' is not a valid e-mail')
    } else {
        var sLst = aLst[1].toLowerCase()
        for (var i = 0; i < okd.length; i++) {
            if (sLst == okd[i]) {
                //    alert(aLst[1] + ' is allowed');-->

           }
       }

            if (i == okd.length) alert(aLst[1] + ' is not allowed.  Please enter an email address with an authorized domain.')

            document.form1.email.select();
            return false;


    }   
}

Answer 1

I'd recommend placing this code into a function, maybe named ValidateEmail() .

In your loop: if you've determined the email is valid, return true; . This will prevent further execution. If that domain doesn't match, have it continue looping to check the others.

If the loop completes without returning true , you'll know it didn't match anything so return false; at the very end.

EDIT: Use try/catch instead:

if (document.form1.email.value.length > 0) {

    var tst = document.form1.email.value;
    var okd = ['bankofamerica.com','baml.com','magner.com','ml.com','ust.com','ustrust.com']
    for (var i = 0; i < okd.length; i++) { okd[i] == okd[i].toLowerCase() }

    try {
        var emailRE = /^[a-zA-Z0-9._+-]+@([a-zA-Z0-9.-]+\.[a-zA-Z]{2,4})$/
        var aLst = emailRE.exec(tst)

        if (!aLst)
            throw (tst + ' is not a valid e-mail');

        // isValidDomain will be changed to 'true' only if it matches an item in the array
        var isValidDomain = false;

        var sLst = aLst[1].toLowerCase()
        for (var i = 0; i < okd.length; i++) {
            if (sLst == okd[i]) {
                isValidDomain = true;
                // We break here because a match has been found - no need to compare against the other domain names.
                break;
            }
        }

        if(!isValidDomain)
            throw (aLst[1] + ' is not allowed.  Please enter an email address with an authorized domain.');

        // If execution reaches here, you know it passed both tests!
        return true;

    }
    catch(err) {

        // This code block runs whenever an error occurs

        alert(err);
        document.form1.email.select();
        return false;
    }
}

throw basically acts like a goto command. It will jump directly to the catch(err) portion of the code.

More info about try, catch, and throw:

• http://www.w3schools.com/js/js_try_catch.asp
• http://www.w3schools.com/js/js_throw.asp

Answer 2

Thank you very much Colin!

I had to remove the following 2 lines to avoid halting the code from running on to next validation field:

              isValidDomain = true;
                    // We break here because a match has been found - no need to compare against the other domain names. 
                    // break - exits code from running on down to next item on page
                }
            }

            if (!isValidDomain)
                throw (aLst[1] + ' is not allowed.  Please enter an email address with an authorized domain.');

            // If execution reaches here, you know it passed both tests! 
         //   return true; - was not needed, stops code from running on page

        }
        catch (err) {