从外部URL获取JSON数据并将其作为纯文本显示在div中

Question

I have an external resource similar to https://www.googleapis.com/freebase/v1/text/en/bob_dylan which returns a JSON. I want to display the value of result key in a div in html (lets say the name of the div is "summary"). Also the value of result key should be displayed in plain text.
The URL returns the json:

{ "result": "Bob Dylan, born Robert Allen Zimmerman, is an American singer-songwriter, author, poet, and painter, who has been a major figure in popular music for five decades. Much of Dylan's most celebrated work dates from the 1960s, when he became an ......." }

The JSON has just the result key, no other keys
Basically I do not want to use anything other than plain HTML and JavaScript. I am a relative beginner to JavaScript and therefore I ask for commented code.

Answer 1

Here is one without using JQuery with pure JavaScript. I used javascript promises and XMLHttpRequest You can try it here on this fiddle

HTML

<div id="result" style="color:red"></div>

JavaScript

var getJSON = function(url) {
  return new Promise(function(resolve, reject) {
    var xhr = new XMLHttpRequest();
    xhr.open('get', url, true);
    xhr.responseType = 'json';
    xhr.onload = function() {
      var status = xhr.status;
      if (status == 200) {
        resolve(xhr.response);
      } else {
        reject(status);
      }
    };
    xhr.send();
  });
};

getJSON('https://www.googleapis.com/freebase/v1/text/en/bob_dylan').then(function(data) {
    alert('Your Json result is:  ' + data.result); //you can comment this, i used it to debug

    result.innerText = data.result; //display the result in an HTML element
}, function(status) { //error detection....
  alert('Something went wrong.');
});

Answer 2

You can do this with JSONP like this:

function insertReply(content) {
    document.getElementById('output').innerHTML = content;
}

// create script element
var script = document.createElement('script');
// assing src with callback name
script.src = 'http://url.to.json?callback=insertReply';
// insert script to document and load content
document.body.appendChild(script);

But source must be aware that you want it to call function passed as callback parameter to it.

With google API it would look like this:

function insertReply(content) {
    document.getElementById('output').innerHTML = content;
}

// create script element
var script = document.createElement('script');
// assing src with callback name
script.src = 'https://www.googleapis.com/freebase/v1/text/en/bob_dylan?callback=insertReply';
// insert script to document and load content
document.body.appendChild(script);

Check how data looks like when you pass callback to google api: https://www.googleapis.com/freebase/v1/text/en/bob_dylan?callback=insertReply

Here is quite good explanation of JSONP: http://en.wikipedia.org/wiki/JSONP

Answer 3

Since it's an external resource you'd need to go with JSONP because of the Same origin policy .
To do that you need to add the querystring parameter callback :

$.getJSON("http://myjsonsource?callback=?", function(data) {
    // Get the element with id summary and set the inner text to the result.
    $('#summary').text(data.result);
});

Answer 4

If you want to use plain javascript, but avoid promises, you can use Rami Sarieddine's solution, but substitute the promise with a callback function like this:

var getJSON = function(url, callback) {
    var xhr = new XMLHttpRequest();
    xhr.open('get', url, true);
    xhr.responseType = 'json';
    xhr.onload = function() {
      var status = xhr.status;
      if (status == 200) {
        callback(null, xhr.response);
      } else {
        callback(status);
      }
    };
    xhr.send();
};

And you would call it like this:

getJSON('https://www.googleapis.com/freebase/v1/text/en/bob_dylan', function(err, data) {
  if (err != null) {
    alert('Something went wrong: ' + err);
  } else {
    alert('Your Json result is:  ' + data.result);
    result.innerText = data.result;
  }
});

Answer 5

You can use $.ajax call to get the value and then put it in the div you want to. One thing you must know is you cannot receive JSON Data. You have to use JSONP.

Code would be like this:

function CallURL()  {
    $.ajax({
        url: 'https://www.googleapis.com/freebase/v1/text/en/bob_dylan',
        type: "GET",
        dataType: "jsonp",
        async: false,
        success: function(msg)  {
            JsonpCallback(msg);
        },
        error: function()  {
            ErrorFunction();
        }
    });
}

function JsonpCallback(json)  {
    document.getElementById('summary').innerHTML = json.result;
}

Answer 6

To display the Json data using Robin Hartman code. You need to add, the below line.

The code he gave gives you Object, object. this code retrieves the data in a better way.

result.innerText =JSON.stringify(data);

Answer 7

Since the desired page will be called from a different domain you need to return jsonp instead of a json .

$.get("http://theSource", {callback : "?" }, "jsonp",  function(data) {
    $('#summary').text(data.result);
});