How can I join string variables when some might be a null?
<p>I have the following variables:</p>

<pre><code>ac, pr, pa, co and it 
</code></pre>

<p>All of these are string variables and some may be null. </p>

<p>Is there a way I can create a new variable called pk that is a combination of the contents of all of these variables. I was thinking simply:</p>

<pre><code>var pk = ac + pr + pa + co + it; 
</code></pre>

<p>However would this be a problem if some varibably was null. I am not sure what happens when I add a null variable to a string.</p>
