You can attach Web Resources to a:
Theme's 
Presentation Template.
Form.
Page.
A Form inherits Web Resources from its Theme. You can add Web Resources specific to the Form and disable ones from the Theme in the Web Resources Tab of the 
Form Properties dialog.
A Page inherits Web Resources from its Form. You can add Web Resources specific to the Page and disable ones from the Theme and the Form in Web Resources properties of the Page.