Calling ASP.Net Code Behind using jQuery AJAX
Here we are specifying success: and failure: to show the kind of return data format we are expecting from the web method.
success: function (response)
When the requested web method is successfully executed and the AJAX request is completed, you can specify a success callback function using the .done() or .success() method in jQuery. This callback function will be invoked to process the output or response from the web method. It allows you to handle and manipulate the data returned from the server after a successful execution, enabling dynamic updates and interactions in your web application.
In jQuery's AJAX functionality, you can specify an error handling callback function using the .fail() or .error() method. This callback function will be executed when an exception or error occurs during the execution of the web method. It allows you to handle and respond to errors, providing a way to deal with unexpected issues that may arise during the AJAX request to the server-side method.C# Source Code
When using AJAX to call a C# method in the code-behind of a web page, the method must be defined as a static method in the code-behind file. This is because AJAX requests are typically stateless, and static methods do not rely on the instance state of the page. Static methods can be called directly without needing to create an instance of the page or control.