parsing JSON using Jquery

Question

I've got a page that will get a quick login check and access a web service for some JSON data. The data it's returning looks like this:

{ 'RESPONSE' : 'INVALID','CAMPAIGNID' : '0','MORELINK' : '' }

The code I'm using to get this data and attempt to pop a modal window based on the information is:

   $.ajax({
            type: "POST",
            contentType: "application/json; charset=utf-8",
            url: "Login.asmx/Logon",
            data: strData,
            dataType: "json",
            success: function (response) {
                $('#divResp').html(response.d);
                $(response.d).each(function(index,item){
                    alert(item.campaignid);
                });
                if (res.indexOf('invalid') >= 0){                       
                    //invalid account information UNP                       
                    foo = "You entered an invalid account number or password";
                    showDialog('screenActivate.asp',test_imgName);
                } 
                if (res.indexOf('none') >=0) {
                    //do not deliver splash screen
                    foo = "No splash screen for YOU!";
                } 
                if (res.indexOf('error') >=0) {
                    //general error
                    foo = "You entered an error";
                }
                if (res.indexOf('frozen') >=0) {
                    //member is locked out from numberous failed attempts
                    foo = "You have too many failed attempts.  Your account has been locked";
                }
                if (res.indexOf('.png') >=0) {
                    imgName = (response.d);
                    showDialog('screenActivate.asp',test_imgName);
                }
                alert(foo);
                $('#divResp').html(response.d);
            }
        });
        $('#divQuery').ajaxError(function(evt, request, settings){
            $('#divResp').html("Web services timeout.  Please try again.");             
        });
    }

The challenge is, either I get no information (Undefined) or as is with this current iteration, an error from Firebug that states uncaught exception: Syntax error, unrecognized expression: 'INVALID'

Am I not parsing the JSON response properly?

Relevant comment to answer

I pasted: "d":"{ 'RESPONSE' : 'INVALID','CAMPAIGNID' : '0','MORELINK' : '' } " into the jsonlint.com and that tool says the JSON is valid. When I attempt to loop through response.d with an each statement, it seems to go character by character.

Always validate the repsonse first e.g. with jsonlint.com. In your case you are definitely not getting a valid JSON. — Daff
– Daff, Commented Nov 21, 2011 at 21:40

jondavidjohn · Accepted Answer · 2011-11-28 15:28:04Z

6

JSON spec requires the use of double quotes (") instead of single quotes (')

Official JSON string parsing Diagram (from http://www.json.org)

http://www.json.org/string.gif

in response to your comment...

ok, here's the deal...

"d":"{ 'RESPONSE' : 'INVALID','CAMPAIGNID' : '0','MORELINK' : '' } "

IS valid JSON... but it is simply an object with a d property that contains the string...

"{ 'RESPONSE' : 'INVALID','CAMPAIGNID' : '0','MORELINK' : '' } "

data that would work the way you expect would look like this...

{"d": {"RESPONSE":"INVALID","CAMPAIGNID":"0","MORELINK":""}}

edited Nov 28, 2011 at 15:28

answered Nov 21, 2011 at 21:37

jondavidjohn

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9 Comments

techmaniac Over a year ago

I pasted: "d":"{ 'RESPONSE' : 'INVALID','CAMPAIGNID' : '0','MORELINK' : '' } " into the jsonlint.com and that tool says the JSON is valid. When I attempt to loop through response.d with an each statement, it seems to go character by character.

techmaniac Over a year ago

alright, I have the JSON properly coded, but I'm still not iterating through the object and getting name/value pairs. If I alert the return it just gives me Object [object] How do I determine the JSON contents? I'd like to know the campaignid, and if there is a morelink.

jondavidjohn Over a year ago

An object is not meant to be iterated over... just do something like this... if (response.d.MORELINK.length > 0) { alert(response.d.CAMPAIGNID); }

techmaniac Over a year ago

I'm getting a response.d.MORELINK is undefined error in Firebug. I'd offer to paste code, but it's exactly as you typed above. This is why I turned to Stack for help, because #$^* just isn't working as it should.

jondavidjohn Over a year ago

Sorry! forgot the wrapping curly braces... fixed it in the answer.

|

Community · Accepted Answer · 2017-05-23 10:34:23Z

1

In addition to @jondavidjohn's answer (+1), you're also referencing the variable res, which is not defined.

edited May 23, 2017 at 10:34

CommunityBot

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answered Nov 21, 2011 at 21:39

Matt Ball

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1 Comment

techmaniac Over a year ago

I removed the declaration for res in troubleshooting the JSON data issue. It was right were the alert() was. :)

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