What does this regular expression maens "/^.+\@(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$/" : <p>Found this technique to verify if the email address is in correct form of not.</p>

<pre><code>function check_email($email) {  
        if( (preg_match('/(@.*@)|(\.\.)|(@\.)|(\.@)|(^\.)/', $email)) || 
            (preg_match('/^.+\@(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$/',$email)) ) { 
             return true;
        } else {
             return false;
        }       
    }
</code></pre>

<p>I Am a newbie in php. What this big regex commands mean? </p>
