2. The method of claim 1 , wherein modifying the at least a portion of the at least one respective attribute of each of the identified one or more elements comprises: adding, by the computing device, 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.
2. The method of claim 1 , wherein modifying the at least a portion of the at least one respective attribute of each of the identified one or more elements comprises: adding, by the computing device, 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. 5. The method of claim 2 , wherein rendering the respective portion of the content comprises: rendering, by the computing device, the respective portion of the content specified by each of the identified one or more elements according to the set of presentation properties indicated by the power mode identifier added to the at least one respective attribute.