Question

I have a javascript function create(tagName, options) and the options variable is a JSON object. like this:

{id: 'test_id', class: 'test_class'}

I would like to know how to get the ‘id/class’ part of the json object.

Answer 1

You can use dot or square bracket notation:

var obj = {id: 'test_id', klass: 'test_class'};
alert(obj.id + ' ' + obj.klass);

or:

var obj = {id: 'test_id', klass: 'test_class'};
alert(obj['id'] + ' ' + obj['klass']);

You can use a for…in loop to get the keys, e.g.:

var obj = {id: 'test_id', klass: 'test_class'};
for(key in obj) {
    alert(key);   
}​

​
Demo: http://jsfiddle.net/2p2gw/5/