Dynamically retrieving JavaScript property value

Question

I am trying to dynamically change the options available to a user. A user will choose either 1 or 2. Once they choose a value, I need to load the options associated with that value. Currently, i have the following:

var json = {'1':[{ 'value':'A', 'text':'Option - A'}, { 'value':'B', 'text':'Option - B'}], '2':[{ 'value':'A', 'text':'Choice - A'}, { 'value':'B', 'text':'Choice - B'}]};

var userWants = '1';
alert(json[userWants]);

Oddly, the alert window just displays ,. I don't understand why. What am I doing wrong?

possible duplicate of [How can I display a JavaScript object?](http://stackoverflow.com/questions/957537/how-can-i-display-a-javascript-object) — Claudiu, Jun 12 '15 at 17:35

score 1 · Accepted Answer · edited May 23 '17 at 12:30

1

Alerts cannot display JSON objects in their natural form. Try logging instead

var json = {'1':[{ 'value':'A', 'text':'Option - A'}, { 'value':'B', 'text':'Option - B'}], '2':[{ 'value':'A', 'text':'Choice - A'}, { 'value':'B', 'text':'Choice - B'}]};

var userWants = '1';
console.log(json[userWants]);

Also, see how to alert javascript object

edited May 23 '17 at 12:30

Community

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answered Jun 12 '15 at 17:32

AmmarCSE

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I see the same thing in the console window that I see in my alert window. – user70192 Jun 12 '15 at 17:38
@user70192, what about using the snippet from my answer? – AmmarCSE Jun 12 '15 at 17:38
The snippet works fine. But not in my actual code. I don't understand why. – user70192 Jun 12 '15 at 17:41
@user70192, can you replicate it in a fiddle so I can try and diagnose? – AmmarCSE Jun 12 '15 at 17:42
The problem is that json is actually a string value in my code. So, I'm now using JSON.parse. However, I'm now getting "Uncaught SyntaxError: Unexpected token '" – user70192 Jun 12 '15 at 17:45
@user70192, it if you can replicate it in a http://jsfiddle.net it will be much easier for us to diagnose – AmmarCSE Jun 12 '15 at 17:47
What exactly is a _pure_ object? `console.log` doesn't display objects in their natural form either. I doubt that anybody would want that. – a better oliver Jun 12 '15 at 17:53

score 1 · Answer 2 · answered Jun 12 '15 at 17:38

Alert converts the object to a string using .toString(), which doesn't give you nice output:

var a = {'value': 'A', 'text': 'Option - A'};
alert(a); // should alert [object Object]

You can use JSON.stringify to display the object nicely:

alert(JSON.stringify(a)); // should alert {"value":"A","text":"Option - A"}

Or:

var json = {'1':[{ 'value':'A', 'text':'Option - A'}, { 'value':'B', 'text':'Option - B'}], '2':[{ 'value':'A', 'text':'Choice - A'}, { 'value':'B', 'text':'Choice - B'}]};
var userWants = '1';
alert(JSON.stringify(json[userWants])); // should alert a nicely-formatted list

score 0 · Answer 3 · answered Jun 12 '15 at 17:43

0

Use console.log(json[userWants]); instead of alert.

You can view the output in console by opening it in Chrome by using the shortcut Ctrl + Shift + J or by using Firebug for Firefox in Firefox.

answered Jun 12 '15 at 17:43

amulya349

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Dynamically retrieving JavaScript property value

3 Answers3