jQuery Ajax未定义

Hello I am newbie here,
I want to ask a few question about jquery
1. How can I hide undefined in the PHP
2. How to name inside name in the API

This is my coding Index.php or

mediamonitoring.comyr.com/jquery.php

Or this

 <!DOCTYPE html>
    <html>
    <head>
        <title>Tutorial</title>
        <link rel='stylesheet' href='css/css.html'/>
    </head>
    <body>
    <h1>jQuery Ajax Tutorial</h1>
    <h2>Name Age</h2>
    <ul id="tutor">

    </ul>


    </body>
    </html>
    <script src='js/jquery.js'></script>
        <script src="js/index.js"></script>
        <script src="js/main.js"></script>


    </body>
    </html>

And my Main.js

$(function(){

  var $tutor = $('#tutor');
  $.ajax({
    type: 'GET',
    url: 'http://rest.learncode.academy/api/johnbob/friends',
    success: function(tutor) {
      $.each(tutor,function(i,ex){//the new item is returned with an ID
        $tutor.append('<li>Name:'+ex.name+', Age '+ex.age+'</li>');
      });
    }
  });
});

no 1. using if, if(variable == null){ //hide }

no 2. change your main.js with this

$(function(){
  var $tutor = $('#tutor');
  $.ajax({
    type: 'GET',
    url: 'http://rest.learncode.academy/api/johnbob/friends',
    success: function(tutor) {
      $.each(tutor,function(i,ex){//the new item is returned with an ID
        if(ex.name != null && ex.age != null){
            console.log(ex);
            $tutor.append('<li>Name:'+ex.name+', Age '+ex.age+'</li>');
        }        
      });
    }
  });
});

This is my answer guyz. Tq

 <html>
      <head>
        <title>JSON/Atom Custom Search API Example</title>
      </head>
      <body>
        <div id="content">
            <input type="text" id="name">
            <button id="add">Add</button>
        </div>

        <script>
         function hndlr(response) {
        for (var i = 0; i < response.items.length; i++) {
            var item = response.items[i];

            // in production code, item.htmlTitle should have the HTML entities escaped.
            document.getElementById("name").innerHTML +="<br>"+"<b>"+ item.title + "</b>"+"<br>" +item.snippet  + "<br>"+"<a href='"+item.link+"'>"+item.displayLink+"</a>" ;

        }
    }
        </script>
        <script src="https://www.googleapis.com/customsearch/v1?q=response&cx=004123968310343535430%3Aaxml6iel9yo&key=AIzaSyDxPcphnrcN9_dfkRkFTbwkv44m1-HI1Hg&callback=hndlr">
        </script>
      </body>
    </html>