How to return back json data from script page?

Question

I had a json file results.json Which shown below. And I had a html file contain some script. This is for retrieve data data. When I am enter into the html page which call a script function get_machFollow(que_script) this function is for receive json file data. The function is works fine and which alert correct output, But after this function return some data to my HTML page.

My JSON file

{"mach_fol_4": {"match_l":
       ["7","8","99"],"attempts":"0","feedback_true":"You are right!",
  "feedback_false":"Sorry! wrong answer."}}

This is my script function. This function is works fine but I can't alert the return value from HTML page. That shows undefined.

function get_machFollow(que_script)
{

        var return_var;
      $.getJSON('results.json', function(data) {
            return_var=data[que_script].match_r;    
            alert(return_var);//Working alert show correct output 
            return return_var;     
                 });

}

This is my html file

   <html>
    <head>
      <script type='text/javascript' src='js/jquery.min.js'></script>
      <script>
         $(document).ready(function(){
             var mach_follow_js;
             mach_follow_js=get_machFollow('mach_fol_4');
             alert(mach_follow_js);//Wrong output
         });
   </head>
    <body>
      <p>Hello world</p>
    </body>
    </html>

$.getJson is an asynchronous call so when you call get_matchFollow and try to alert the response in next line, response from ajax has not come.That's why it is coming as undefined — Sachin Jain
– Sachin Jain, Commented Dec 6, 2013 at 4:29
possible duplicate of How to return the response from an AJAX call? — Felix Kling
– Felix Kling, Commented Dec 6, 2013 at 4:46

user1889665 · Accepted Answer · 2013-12-06 04:23:28Z

1

are you intending return return_var; to be inside the get_machFollow scope, because right now its inside the jquery function scope and will not return value to the main page

answered Dec 6, 2013 at 4:23

user1889665

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3 Comments

Adarsh M Pallickal Over a year ago

Then how can I get this values? I need a solution not advice.

user1889665 Over a year ago

I have not tried this with jquery but check what the $.getJSON method is returning if its not void, you might be able to assign return_var= $.getJSON..., but keep the return in the getJSON and add a new one to the outer function

Adarsh M Pallickal Over a year ago

$.getJSON return some useless objects for show the function is ready.

Darshan Parihar · Accepted Answer · 2013-12-06 05:06:49Z

Here below JSON data fetched by AJAX. It passing JSON Data Object in Alert. You can use it as you want. also can Iterate data using for loop or $.each function.

$(document).ready(function(){
    var mach_follow_js;
    // mach_follow_js=get_machFollow('mach_fol_4');

    //JSON Data Fetched by AJAX
    $.ajax('results.json',{
        type:'GET',
        dataType: "json",
        jsonCallback: 'successCallback',               
        async: true,
        beforeSend: function () {
        //if you want to show loader
    },
    complete: function () {
        //hide loader after download data
    },
    success: function (resultJSON) {                                       
        mach_follow_js = resultJSON;        // assigning to Global variable ProductResult                   
        alert(mach_follow_js);
        console.log(mach_follow_js);
    },
    error: function (request, error) {
        alert('Network error has occurred please try again!');//error
    }
    })                              

});

Sachin Jain · Accepted Answer · 2013-12-06 04:32:36Z

0

There are multiple ways by which you can do it. One of them is pass a callback handler to your method which will be called when you get the response. Try this:

function get_machFollow(que_script, sCallback)
{
      var return_var;
      $.getJSON('results.json', function(data) {
            return_var=data[que_script].match_r;    
            alert(return_var);//Working alert show correct output 
            sCallback.call(null /* context */, return_var);      
       });

}

$(document).ready(function(){
    var mach_follow_js;
    get_machFollow('mach_fol_4', function(output) {
        alert(output);
        match_follow_js = output;
   });
});

answered Dec 6, 2013 at 4:32

Sachin Jain

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Comments

user2801382 · Accepted Answer · 2013-12-06 08:33:19Z

0

Use ajax callback function $.getJSON() is actually an ajax function. So you need to apply callback to perform this action.

answered Dec 6, 2013 at 8:33

user2801382

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