如何使用Ajax从＃facebook graph url查找返回的json对象获取特定字段

Question

I am trying to get a particular field values from a json object returned facebook graph api using javascript ajax call.

I am trying following code to get the cover field from json object but its not accessible . for referenced http://jsfiddle.net/GD4PC/ her is the code

    xmlhttp.onreadystatechange = function() {
    if (xmlhttp.readyState == 4 ) {
       if(xmlhttp.status == 200){
           var ur="https://facebook.com/344128252278047";
           var res= JSON.parse(xmlhttp.responseText);
           console.log(res);
           document.getElementById("myDiv").innerHTML=res.cover;

       }
       else if(xmlhttp.status == 400) {
          alert('There was an error 400')
       }
       else {
           alert('something else other than 200 was returned')
       }

Answer 1

If you will look at your content of res you will know the cover field is not directly accessible.

To access cover try this.

res[ur].cover

To access that source which you've mentioned in comment you should say

res[ur].cover.source

Because your object has a field "https://facebook.com/344128252278047" which is same as ur . In that field there is a field cover .