Issue with Syntax: Error encountered while attempting to parse JSON data for protovis load operation

Question

Issue with Syntax: Error encountered while attempting to parse JSON data for protovis load operation

Greetings! I am currently diving into the world of protovis, and things have been going well so far. However, I have encountered a problem that has me stumped.

Below is the code snippet I am working with. (I have ensured that the latest jquery is loaded in my headers)

<script type="text/javascript+protovis"> 
var dataURL = "http://eagereyes.org/media/2010/protovis-primer/earthquakes.json";

var JSONdata = $.ajax({ type: "GET", url: dataURL, async: false }).responseText;
var earthquakes = JSON.parse(JSONdata);

var width = 560;
var height = 245;

var barWidth = width/earthquakes.length;
var gap = 2;

new pv.Panel().width(width).height(height+5)
    .add(pv.Bar)
        .data(earthquakes)
        .bottom(0)
        .width(barWidth-gap)
        .height(function(d) d.Magnitude * (height/9))
        .left(function() this.index * barWidth)
    .root.render();

Upon testing this in Firefox, I encountered the following alert:

Syntax: Error JSON.parse

I have already validated the JSON on . Therefore, it seems that the issue lies elsewhere.

Does anyone have any insights on what might be causing this error?

Edit

As an additional test, I tried loading the same data using the protoviewer app: , and it worked fine. This suggests that the issue may indeed be within the code itself.

javascript ajax json protovis

Answer 1

Answer №1

Have you considered using an asynchronous callback instead of the current synchronous method? For example:

var dataURL = "http://creativeblog.com/data/earthquakes.json";

$.ajax({
  type: "GET",
  url: dataURL,
  success: function(response) {
    var earthquakes = JSON.parse(JSONdata);

    var width = 560;
    var height = 245;

    var barWidth = width/earthquakes.length;
    var gap = 2;

    new pv.Panel().width(width).height(height+5)
        .add(pv.Bar)
            .data(earthquakes)
            .bottom(0)
            .width(barWidth-gap)
            .height(function(d) d.Magnitude * (height/9))
            .left(function() this.index * barWidth)
        .root.render();     
  }
});

Additionally, is the JSON file located on the same server as the page making the request, in this case exactly http://creativeblog.com?

Lastly, you can simplify the process by using the dataType: 'json' parameter with $.ajax(), which will automatically deserialize JSON and utilize JSON.parse() where needed.

Answer 2

Have you considered using an asynchronous callback instead of the current synchronous method? For example:

var dataURL = "http://creativeblog.com/data/earthquakes.json";

$.ajax({
  type: "GET",
  url: dataURL,
  success: function(response) {
    var earthquakes = JSON.parse(JSONdata);

    var width = 560;
    var height = 245;

    var barWidth = width/earthquakes.length;
    var gap = 2;

    new pv.Panel().width(width).height(height+5)
        .add(pv.Bar)
            .data(earthquakes)
            .bottom(0)
            .width(barWidth-gap)
            .height(function(d) d.Magnitude * (height/9))
            .left(function() this.index * barWidth)
        .root.render();     
  }
});

Additionally, is the JSON file located on the same server as the page making the request, in this case exactly http://creativeblog.com?

Lastly, you can simplify the process by using the dataType: 'json' parameter with $.ajax(), which will automatically deserialize JSON and utilize JSON.parse() where needed.

Answer 3

Answer №2

Make sure to include a semi-colon ; at the conclusion of your answer

Answer 4

Make sure to include a semi-colon ; at the conclusion of your answer

Answer 5

Answer №3

Are you currently using a web browser? It's possible that some browsers may not have the JSON object defined. If that's the case, you can easily fix this issue by downloading a script from the following URL which will define the JSON object for you.

https://github.com/douglascrockford/JSON-js

To check if the JSON object is defined, simply use the following code:

alert(JSON);

Update:

Now, I recommend verifying whether the JSON data returned from your ajax call is correct. Modify your code to print out the JSON response from the ajax call.

var JSONdata = $.ajax({ type: "GET", url: dataURL, async: false }).responseText;
alert(JSONdata);
var earthquakes = JSON.parse(JSONdata);

Answer 6

Are you currently using a web browser? It's possible that some browsers may not have the JSON object defined. If that's the case, you can easily fix this issue by downloading a script from the following URL which will define the JSON object for you.

https://github.com/douglascrockford/JSON-js

To check if the JSON object is defined, simply use the following code:

alert(JSON);

Update:

Now, I recommend verifying whether the JSON data returned from your ajax call is correct. Modify your code to print out the JSON response from the ajax call.

var JSONdata = $.ajax({ type: "GET", url: dataURL, async: false }).responseText;
alert(JSONdata);
var earthquakes = JSON.parse(JSONdata);

Answer 7

Answer №4

$.ajax({
            type: "POST",
            url: "updateEditingInfo.php",
            data: userDetails,
            success: function(response){
                         userInfo = JSON.parse(response);
                         $("input[name = 'username']").val(userInfo.username);
                         $("input[name='email']").val(userInfo.email);
                         $("input[name='password']").val(userInfo.password);
                    },
            error: function(response){
                     alert("Oops! Something went wrong." + response);
                   }
        });

Answer 8

$.ajax({
            type: "POST",
            url: "updateEditingInfo.php",
            data: userDetails,
            success: function(response){
                         userInfo = JSON.parse(response);
                         $("input[name = 'username']").val(userInfo.username);
                         $("input[name='email']").val(userInfo.email);
                         $("input[name='password']").val(userInfo.password);
                    },
            error: function(response){
                     alert("Oops! Something went wrong." + response);
                   }
        });

Issue with Syntax: Error encountered while attempting to parse JSON data for protovis load operation

Answer №1

Answer №2

Answer №3

Answer №4

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