Run JavaScript from C# ASP.NET

I'm trying to run a javascript function from the code behind in C#. I looked at many resourses on internet but so far no luck. This does not even work with a very simple sample code that I have:

Code behind:

  protected void Button2_Click(object sender, EventArgs e)
  {
       ScriptManager.RegisterStartupScript(this,GetType(),"a","a();", true);
  }

In my aspx file:

 <script type="text/javascript">
         function a()
         {
             var i = 0;

         }
  </script>

When I run this I get :

0x800a1391 - JavaScript runtime error: 'a' is undefined

Note :

Also tried :

• ScriptManager.RegisterStartupScript(this,GetType(),"a","a()", true);
• ScriptManager.RegisterStartupScript(this,GetType(),"a","a", true);

Still getting the same error.