jQuery: add an attribute to multiple elements with the same id or class

In this video you will see how you can add an attribute to multiple elements with the same id or class with jQuery.

[Silencer]

Working on a Chrome extension in order to add additional functionality to a specific website. I have to deal with the fact that the developers used ids instead of classes, so this workaround was very helpful :)

[markbrown]

id must be unique otherwise it is an invalid document. simply use class='new' and $('.new') rather than this unnecessary workaround

[MohitManuja]

crap, u can never ever, never ever use multiple instances of an id