Question

I am a little confused about the benefits or conc using scriptmanager with ajax calls or use JQuery to direct call webmethods.

Can some one give me some hints about this issue? when to use which? there is any different while dealing with JSON?

Answer 1

I think the MSDN ScriptManager control page does a good job of summing up the features –

• Register script that is compatible with partial-page updates.

• In order to manage dependencies
  between your script and the core
  library, any script that you register
  is loaded after the Microsoft AJAX
  Library script.

• Specify whether release or debug scripts are sent to the browser.

• Provide access to Web service methods from script by registering Web
  services with the ScriptManager
  control.

• Provide access to ASP.NET authentication, role, and profile
  application services from client
  script by registering these services
  with the ScriptManager control.

• Enable culture-specific display of ECMAScript (JavaScript) Date,
  Number, and String functions in the
  browser.

• Access localization resources for embedded script files or for
  stand-alone script files by using the
  ResourceUICultures property of the
  ScriptReference control.

• Register server controls that implement the IExtenderControl or
  IScriptControl interfaces with the
  ScriptManager control so that script
  required by client components and
  behaviors is rendered.

Essentially the ScriptManager does what it says, manages your scripts without too much concern on your part with writing the JavaScript "glue" to do it yourself.

Of course, there is (some might say significant) overhead to including the ScriptManager control, not least the amount of additional requests made for script resources and the size of the generated proxy classes to call web services and page methods. This may not be so important when developing an intranet application where bandwidth and network speed are likely to be less of a problem compared to developing an application for the internet, but it’s important to be aware of, nonetheless.

If you’re comfortable with a JavaScript library that is capable of replacing all features of the ScriptManager whilst also being lighter in weight and as fast to get things done, then that sounds like a good case to not use the ScriptManager.

In terms of dealing with JSON, both jQuery and the ScriptManager handle it fine. IIRC, JSON is the default data type for Page Methods and Web Services in .NET (although something is reminding me that this was not always the case).