Validate a email field with jquery : <p>I need to validate a email field with jquery but the program doesn't work.</p>

<pre><code>   var email_form=$('#email');
        if(email_form!=null){
console.log("HI");
            $('#email').on('input', function(){
                console.log("show ");
            });
        }
</code></pre>

<p>The program prints "HI" but it doesn't print in "show".My purpose is to every time that an user writes a character in a email field I must validate this text. Anyone can help me?</p>
