Display values in JSON array

**TryingToLearn** · Dec 2, 2012 22:55

I am hoping a second set of eyes can help me find my error. I am creating a basic JSON object and trying to display the values in the JSON object. Field 1 displays properly, but fields 2 & 3 display as undefined. Can anyone see what my problem is?

Thanks in advance for your time.

Code:

<html>
<head>
    <title>String to JSON in JavaScript</title>
    <script type="text/javascript">

	var mockJSON = 
{
	"testing" :
	[
		{ "field1" : "field1" },
		{ "field2" : "field2" },
		{ "field3" : "field3" }
	]
};
	
	function createJSON() {
		alert( "field1: " + mockJSON.testing[0].field1 );
		alert( "field2: " + mockJSON.testing[0].field2 );
		alert( "field3: " + mockJSON.testing[0].field3 );
	}
	
    </script>
</head>
<body onLoad="">
	<a href="javascript:createJSON();">Build JSON</a>
</body>
</html>

**AussieJohn** · Dec 3, 2012 02:40

Originally Posted by TryingToLearn

I am hoping a second set of eyes can help me find my error. I am creating a basic JSON object and trying to display the values in the JSON object. Field 1 displays properly, but fields 2 & 3 display as undefined. Can anyone see what my problem is?

You're trying to access the same array item which doesn't have those properties.

i.e.

Code javascript:

var mockJSON = {
    "testing" : [
        { "field1" : "field1" }, // mockJSON.testing[0].field1  <<<--- mockJSON.testing[0].field2 doesn't exist 
        { "field2" : "field2" }, // mockJSON.testing[1].field2
        { "field3" : "field3" }  // mockJSON.testing[2].field3
    ]
};

If you wanted to access those fields without the array you could rewrite the object without it:

Code javascript:

var mockJSON2 = {
    "testing" : {
        "field1" : "field1", // mockJSON.testing.field1
        "field2" : "field2", // mockJSON.testing.field2
        "field3" : "field3"  // mockJSON.testing.field3
    }
};

**TryingToLearn** · Dec 3, 2012 12:25

Thank you for the feedback… I see your point. I was referring to elements that did not exist. The field name should be repeated since it is the value in the JSON object. Here is my updated code.

Code:

<html>
<head>
    <title>String to JSON in JavaScript</title>
    <script type="text/javascript">

	var mockJSON = 
{
	"testing" :
	[
		{ "field1" : "1st iteration" },
		{ "field1" : "2nd iteration" },
		{ "field1" : "3rd iteration" }
	]
};
	
	function createJSON() {
		alert( "1: " + mockJSON.testing[0].field1 );
		alert( "2: " + mockJSON.testing[1].field1 );
		alert( "3: " + mockJSON.testing[2].field1 );
	}
	
    </script>
</head>
<body onLoad="">
	<a href="javascript:createJSON();">Build JSON</a>
</body>
</html>

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