title: error CS0234: The type or namespace name 'Script' does not exist in the namespace 'System.Web'
body: <p>I am trying to use <code>JavaScriptSerializer</code> in my application.</p>
  
  <p>I initially received </p>
  
  <blockquote>
    <p>Cannot find JavaScriptSerializer</p>
  </blockquote>
  
  <p>and I solved it by adding:</p>
  
  <pre><code>using System.Web.Script.Serialization;
  </code></pre>
  
  <p>But then the sub-keyword <code>Script</code> is underlined with a blue line:</p>
  
  <blockquote>
    <p>The type or namespace 'Script' does not exist in the namespace
    'System.Web' (are you missing an assembly reference?)</p>
  </blockquote>
  
  <p>So I added to the project a reference to:</p>
  
  <blockquote>
    <p>C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.0\System.Web.Extensions.dll</p>
  </blockquote>
  
  <p>That didn't help. I am still receiving the same blue underline with same error. The reference is marked with an exclamation mark yellow warning:</p>
  
  <p><img src="https://i.stack.imgur.com/brkfO.png" alt="enter image description here"></p>
  
  <p>I tried the suggested solutions on <a href="https://stackoverflow.com/q/7000811/1088880">this thread</a>, but as @user781490 indicated, they didn't help in my situation.</p>
  
  <p>Any idea how to resolve this?</p>