title: The name 'ClientScript' does not exist in the current context
body: <p>I have a behindcode javascript. it is to show a javascript dialog box. </p>
  
  <p>however, it keep show this error </p>
  
  <pre><code>The name 'ClientScript' does not exist in the current context
  </code></pre>
  
  <p>This code was put inside masterpage. I had also use the exactly same code at other aspx file, and it work out fine apart from this.. </p>
  
  <p>here is my code: </p>
  
  <pre><code>   protected void Button2_Click(object sender, EventArgs e)
      {
          string message = "Order Placed Successfully.";
          System.Text.StringBuilder sb = new System.Text.StringBuilder();
          sb.Append("&lt;script type = 'text/javascript'&gt;");
          sb.Append("window.onload=function(){");
          sb.Append("alert('");
          sb.Append(message);
          sb.Append("')};");
          sb.Append("&lt;/script&gt;");
          ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", sb.ToString()); string script = "alert('abc');";
  
      }   
  </code></pre>