Working example: How to populate "my_textfield" on the stage with some json data?

add a component to your project (or otherwise include jquery) and use:

function sendDataF(methodS,dataTypeS,urlS,dataObj,f){

$.ajax({

    url : urlS,

    data : dataObj,

    type : methodS,

    dataType : dataTypeS,

    success : f,

    error: function(ts) { console.log(ts.responseStatus); },

    error : function(xhr, status) {

        var errorS = '';

        for(s in xhr){

            errorS += s+' : '+xhr+'\n';

        }

        alert('Sorry, there was a problem!\n'+errorS+'\nstatus:'+status);

    },

    complete : function(xhr, status) {

        var errorS = '';

        for(s in xhr){

            errorS += s+' : '+xhr+'\n';

        }

       // alert('request complete!\n'+errorS+'\nstatus: '+status);

       //console.log('request complete!\n'+errorS+'\nstatus: '+status);

    }

});

}

function parseResponseF(s){

    //parse s

}

sendDataF("POST","json","yourjasonfilename.json",null,parseResponseF);