js password strength formula code example

Example: password strength checker javascript

<script language="javascript">
    function passwordChanged() {
        var strength = document.getElementById('strength');
        var strongRegex = new RegExp("^(?=.{14,})(?=.*[A-Z])(?=.*[a-z])(?=.*[0-9])(?=.*\\W).*$", "g");
        var mediumRegex = new RegExp("^(?=.{10,})(((?=.*[A-Z])(?=.*[a-z]))|((?=.*[A-Z])(?=.*[0-9]))|((?=.*[a-z])(?=.*[0-9]))).*$", "g");
        var enoughRegex = new RegExp("(?=.{8,}).*", "g");
        var pwd = document.getElementById("password");
        if (pwd.value.length == 0) {
            strength.innerHTML = 'Type Password';
        } else if (false == enoughRegex.test(pwd.value)) {
            strength.innerHTML = 'More Characters';
        } else if (strongRegex.test(pwd.value)) {
            strength.innerHTML = '<span style="color:green">Strong!</span>';
        } else if (mediumRegex.test(pwd.value)) {
            strength.innerHTML = '<span style="color:orange">Medium!</span>';
        } else {
            strength.innerHTML = '<span style="color:red">Weak!</span>';
        }
    }
</script>
<input name="password" id="password" type="text" size="15" maxlength="100" onkeyup="return passwordChanged();" />
<span id="strength">Type Password</span>