Comments on: Simplify calling ASP.NET AJAX services from jQuery

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Sat, 13 Feb 2010 22:40:33 +0000

[...] · Simplify calling ASP.NET AJAX services from jQuery [...]

By: Chris Haines

Chris Haines — Thu, 21 Jan 2010 17:14:00 +0000

Adam, you got it. This is a pain as it’s broken my app all over! Thanks for explaining.

By: Adam Weber

Adam Weber — Sun, 17 Jan 2010 17:08:35 +0000

I think I actually answered my own question! First time for everything :)

Anyways, in my testing with jQuery 1.4, the dataFilter you outline works just fine if msg.d contains JSON.

However, if msg.d contains a simple string value (e.g. HTML), then the dataFilter in combination with jQuery’s post-filter JSON parsing will throw an exception IF the ajax dataType option is “json” or if you don’t specify a dataType and the contentType contains “json”.

According to the jQuery 1.4 documentation for the ‘dataType’ option: “If no dataType is specified, jQuery will intelligently try to get the results, based on the MIME type of the response.”

Since you need to specify a contentType (MIME type) of ‘application/json’ when working against ASP.NET webservices, jQuery will attempt to parse msg.d as JSON, even if it’s just a string.

So, and maybe this is just good practice anyways, with jQuery 1.4 be sure to set the ‘dataType’ option in your ajax request to “html” or “text” if msg.d is going to contain a string value. Only set the ‘dataType’ option to “json” if msg.d is going to contain JSON (properly formatted).

Hope this makes sense and helps someone else!

P.S. Thanks for all the great posts Dave, your site is a fantastic resource!

By: Adam Weber

Adam Weber — Sun, 17 Jan 2010 15:30:35 +0000

Now that jQuery 1.4 has been released and uses JSON.parse natively, is the dataFilter no longer necessary?

By: valse

valse — Mon, 19 Oct 2009 16:54:05 +0000

I must edit latest jTemplate’s source (0.7.8) adding on every jQuery.ajax call (if needed)

type: "GET",
contentType: "application/x-www-form-urlencoded",
data: "",

jquery, web services, json, jtemplate… is good and fast solution!

By: Dave Ward

Dave Ward — Thu, 08 Oct 2009 18:57:39 +0000

$.getJSON is just a shortcut wrapper around a particular $.ajax call. Under the hood, they all work the same way (and $.ajaxSetup affects them all).

jQuery doesn’t use JSON.parse yet, but will in the next release (the change is already checked in, just pending a release). It currently uses eval() for any JSON parsing.

By: Jquery JSON Parser

Jquery JSON Parser — Thu, 08 Oct 2009 14:48:31 +0000

I don’t understand something.
When I use .getJSON doesn’t it parse my json?

Should i use the eval? DOes jquery uses the JSON.parse?

By: Dave Ward

Dave Ward — Fri, 18 Sep 2009 01:51:38 +0000

You’re right, there’s no $.get() in the latest version. Looks like that changed in 0.7.5.

$.ajaxSetup shouldn’t override that explicit GET, but the contentType still needs to be explicitly specified there in the options array.

By: Jamie

Jamie — Tue, 15 Sep 2009 14:12:58 +0000

I’m not seeing where there’s a $.get() call in the processTemplateURL function (version 0.7.8). Can you be more specific in the change made to jTemplates?

By: Asheesh Soni

Asheesh Soni — Tue, 01 Sep 2009 07:17:25 +0000

I was having issues getting jQueryUI tabs to work in ajax mode and then I realized I had included $.ajaxSetup in my Master Page with defaults for type (POST), contentType (json), dataFilter (for .d) etc.

I changed my ajaxSetup as follows, and now UI Tabs work fine in ajax mode and thanks to Dave, I don’t have to worry about .d either :)

$.ajaxSetup(
{
  data: "{}",
  dataFilter: function(data)
  {
    var msg;
    try
    {
      if (typeof (JSON) !== 'undefined' && 
          typeof (JSON.parse) === 'function')
        msg = JSON.parse(data);
      else
        msg = eval('(' + data + ')');
    }
    catch (err)
    {
      msg = data;
    }
    if (msg.hasOwnProperty('d'))
      return msg.d;
    else
      return msg;
  }
});

By: Populating Table Data using jQuery – My Tech World

Populating Table Data using jQuery – My Tech World — Mon, 10 Aug 2009 11:37:39 +0000

[...] don’t need to go into detail about this part since Dave Ward has already done it for me. Thanks, [...]

By: Dave Ward

Dave Ward — Mon, 10 Aug 2009 01:51:39 +0000

I edited jTemplates’ processTemplateURL function to use an explicit $.ajax() call with the correct parameters, instead of $.get() that it uses by default.

By: francois

francois — Wed, 05 Aug 2009 07:15:54 +0000

great article .i have a question.you said “Fixing that problem wasn’t difficult, but it also wasn’t immediately obvious what had caused the issue in the first place”

could you please tell us about the fix.how i can use the default settings with j templates ate the same time.

By: Dave Ward

Dave Ward — Tue, 04 Aug 2009 16:06:27 +0000

Did you also change the URL of your $.ajax() call to use HTTPS? Calls will fail if the protocol of the page and $.ajax URL don’t match.

By: Anz

Anz — Tue, 04 Aug 2009 07:15:35 +0000

Hi,
I am using JQuery+ Pagemethods for most of my ajax needs. Its excellent but now I have a problem with https page..
I have a captcha refresh script in my registration page and the refresh will happen through JQuery/Pagemethod.. Its working excellent without HTTPS but when I made my registation page SSL, the AJAX call is showing error 500 with following Response

{“Message”:”Authentication failed.”,”StackTrace”:null,”ExceptionType”:”System.InvalidOperationException”
}

Do you know how to solve this?

Thanks and Best Regards
Anz