how to check null values in javascript?
<p>how can i check null values in javascript?
i wrote bellow code but it didn't worked.</p>

<pre><code>if(pass == null || cpass == null || email == null || cemail == null || user == null)
                    {
                        alert("fill all columns");
                        return false;
                    }
</code></pre>

<p>and how can i find out errors of my program in javascripts?</p>
