Reading a value from the Web.config file of an ASP .NET Web Application using Javascript

To read a value from the web.config file of an ASP .NET Web Application using javascript, you can do the following:

1. In your web.config file, add a new <appSettings> with the key and value that you wish for the javascript code to obtain.  In this example, here is the new <appSettings> node, I'm going to reference:
   
   

   <appSettings>
        <add key="Environment" value="TEST" />
   </appSettings>

   
   
   
2. In the HTML code of my default.aspx page, I'm going to add the following javascript function that's going to reference the new <appSettings> node that I just added:
   
   

   function getEnvironment() { 
        var environment = '<%= ConfigurationManager.AppSettings["Environment"].ToString() %>';
        alert(environment);
   }

All you have to do is call this function at an appropriate location in your code and it will obtain the value of the respective <appSettings> node.  Naturally, you'll want to swap out the alert call with some valid code, but the idea of this example is to get you rolling.