ASP.Net: Read (Get) AppSettings Key Value from Web.Config file in JavaScript

Here Mudassar Ahmed Khan has explained with an example, how to read (get) value from the AppSettings section of the Web.Config file in JavaScript in ASP.Net using C# and VB.Net. It is not possible to read the AppSetting value directly in JavaScript and hence using JavaScript XmlHttpRequest (XHR), an AJAX call will be made to a WebMethod which will read the AppSetting value and return it to the JavaScript function.