Difference between calling function and referencing function?
<p>Look at the following code:</p>

<pre><code>window.onload = someFunction;
</code></pre>

<p>Many times I see the use of this kind of code and even I use the same. But, there are still few things unclear. </p>

<ol>
<li>The above is a call to <code>someFunction</code> as soon as the page loads, right. But, aren't we supposed to call a function with brackets <code>()</code>?</li>
<li>From my understanding, we are just assigning <code>someFunction</code> to <code>window.onload</code>, therefore can we or shouldn't we call <code>window.onload()</code>;</li>
<li>Are there such cases, when <code>functionName()</code> and <code>functionName</code> becames interchangeable. Because at many places, and in various API, I have seen calling the function without brackets.</li>
</ol>
