Question

I use this in PHP to ensure a variable contains only alpha or numeric:

if(preg_match('/\W/', $username)) {
    $loginerror[]=$siteLanguage->usernameinvalidchars;
};

How can I do the same check in JQUERY?

thx

Answer 1

First of all, you do not need jQuery for this – raw JavaScript is enough. More specifically: test() method of RegExp object is enough (see documentation).

Second, you can do this similarly to the following:

if (/\W/.test(username)){
    // non-alphanumeric character found in username
    loginerror.push(siteLanguage.usernameinvalidchars);
}

where str is your string and /\W/.test(username) returns true if there is non-alphanumeric character within username (false otherwise). See this jsfiddle for proof.