I found this gist to detect changes on specified fiels of a object : https://gist.github.com/3138469
But it bind an event only on one field.
Someone know a function or a tricks to detect change on an entire Javascript Object ?
2019 Update: These days this can be achieved using Proxy API in a much more efficient manner. The on-change library uses the Proxy API behind the scene to make this even easier.
2012 Update: I've just noticed that the author of Watch.js is referencing a library with much broader browsers' support. MultiGetSet.JS
When I want to achieve this I usually use Watch.js, you can watch a whole object or one attribute.