Question

<script type="text/javascript">
var X = {
   a: [{name:john, phone:777},{name:john, phone:777},{name:john, phone:777}],
   b: [{name:john, phone:777},{name:john, phone:777},{name:john, phone:777}],
   c: [{name:john, phone:777},{name:john, phone:777},{name:john, phone:777}],
   d: [{name:john, phone:777},{name:john, phone:777},{name:john, phone:777}]


}

var str = JSON.stringify(X);
alert(str);


</script>

What’s wrong with this object?? It alerts “Uncaught ReferenceError: john is not defined”
How come??

Answer 1

You need quotes around john. Otherwise it is referring to an variable/object that has not been created:

var X = {
  a: [{name:"john", phone:777},{name:"john", phone:777},{name:"john", phone:777}]
...

Your code would be valid if john was previously defined:

var john = "john";
var X = {
  a: [{name:john, phone:777},{name:john, phone:777},{name:john, phone:777}]
  ...

Now john is a variable representing the string “john”, and the JSON is valid.