<div>
You will get an undefined error if you have not declared the function before.
</div>


You will get an undefined error if you have not declared the function before.

<div>
<div class="content wysiwyg-content">
Is it possible to call a function from within a function? But if function isnt declared do nothing?<br />
<br />

<pre><code id="code-10-28318781-1">function showUrlInDialog(options){
     (options.onOpen || function () { /*Do nothing*/ });
     }

showUrlInDialog({
     myValue1:27,
     myValue2:45,
     onOpen: function () { alert('hello'); }
     });</code></pre>
</div>
</div>


Is it possible to call a function from within a function? But if function isnt declared do nothing?

(CODE)

Call function

JavaScript is a dynamic, object-based language commonly used for client-side scripting in web browsers. Recently, server side JavaScript frameworks have also emerged. JavaScript runs on nearly every operating system and  in almost every mainstream web browser.