Validate And Filter Email Address With Regex?

What's the best way to disallow free email service emails (e.g. Gmail, Yahoo, Hotmail) using RegEx and Javascript email field validation? ^.*@(?!(aol\.com$|yahoo\.com$|hotmail\.com

Solution 1:

One of thousands of acceptable ways to get there - not that yours isn't acceptable...

function isGoodEmail(email) {
    if(isValidEmail(email)) {
        if(/(aol|gmail|yahoo|hotmail)\.com$/.test(email)) {
           alert(' valid email, but not for this site.  No free service emails!');
           return false;
        }
        return true;
    }
    return false;
}

function isValidEmail(email) {
  // implement using any of the email regexp's available 
}