Missing section declaration (system.web.extensions)
<p>I am encountering an issue wherein when I added the system.web.extensions on my web.config, I am getting the error saying, "Missing section declaration(system.web.extensions)".</p>

<p>The main root of this issue comes from another issue, which says "System.InvalidOPerationException: Error during serialization or deserialization using the JSON JavaScriptSerializer.", so when I researched for answers, they said that you need to add this configuration on your web.config,</p>

<pre><code>&lt;system.web.extensions&gt;
   &lt;scripting&gt;
    &lt;webServices&gt;
    &lt;jsonSerialization maxJsonLength="500000"&gt;
    &lt;/jsonSerialization&gt;
    &lt;/webServices&gt;
   &lt;/scripting&gt;
&lt;/system.web.extensions&gt;
</code></pre>

<p>But when I add this code, I am getting the "missing declaration issue", question is, what file/s do I need to modify so that the system.web.extensions can be read by my web.config?  I am getting stuck here.</p>

<p>@edit:  My web application is running on a V2.0, is this achievable using this version?</p>

<p>Thanks.</p>
