How to access JSON Array elements returned from an AJAX response

how to access JSON array elements for the following JSON Code? further how do i calcula开发者_如何转开发te the size of the returned object array?

[
{
lastInvAmt: 0
bwHrs: 0
nbwHrs: 0
unbilledAmt: 0
unbilledHrs: 0
dbID: 0`
},{
lastInvAmt: 0
bwHrs: 0
nbwHrs: 0
unbilledAmt: 0
unbilledHrs: 0
dbID: 0`
}]

Why can't you assign it to variable? Or I don't understand anything? :)

edited to work with json string

var ar = eval('[
{
lastInvAmt: 0
bwHrs: 0
nbwHrs: 0
unbilledAmt: 0
unbilledHrs: 0
dbID: 0
},{
lastInvAmt: 0
bwHrs: 0
nbwHrs: 0
unbilledAmt: 0
unbilledHrs: 0
dbID: 0
}]');

Why do you have single quote dbID: 0`. Is it spelling error?