11. A computing device comprising: at least one processor; and at least one module operable by the at least one processor to: detect a change to a power mode of the computing device; responsive to detecting the change to the power mode, process, from among a set of elements within a page of content that each specify a respective portion of the content in accordance with a markup language, the page of content to identify one or more elements of the set of elements that each have at least one respective attribute designated to be modified in response to the change to the power mode; modify, based on the change to the power mode, at least a portion of the at least one respective attribute of each of the identified one or more elements to associate the respective portion of the content specified by each of the identified one or more elements with a set of presentation properties; and render, for display in accordance with the set of presentation properties, the respective portion of the content specified by each of the identified one or more elements.
11. A computing device comprising: at least one processor; and at least one module operable by the at least one processor to: detect a change to a power mode of the computing device; responsive to detecting the change to the power mode, process, from among a set of elements within a page of content that each specify a respective portion of the content in accordance with a markup language, the page of content to identify one or more elements of the set of elements that each have at least one respective attribute designated to be modified in response to the change to the power mode; modify, based on the change to the power mode, at least a portion of the at least one respective attribute of each of the identified one or more elements to associate the respective portion of the content specified by each of the identified one or more elements with a set of presentation properties; and render, for display in accordance with the set of presentation properties, the respective portion of the content specified by each of the identified one or more elements. 12. The computing device of claim 11 , wherein the at least one module is further operable by the at least on processor to modify the at least a portion of the at least one respective attribute of each of the identified one or more elements by at least adding a power mode identifier associated with the set of presentation properties to the at least one respective attribute of each of the identified one or more elements, wherein the power mode identifier indicates one of a set of low-power presentation properties and a set of full-power presentation properties.