11. A system for efficiently identifying dynamic content of a webpage comprising: a device intermediary to a plurality of clients and a plurality of servers; a comparison engine of the device: accessing a first stored data file representing a first version of a web page and first abstract syntax tree corresponding to the first stored data file, the abstract syntax tree comprising at least one static node, the static node including stored content; and identifying non-matching dynamic content between the first stored data file and a second data file representing a second version of the web page without using a second abstract syntax tree corresponding to the second data file; and a virtual browser of a plurality of virtual browsers executing on the device and replacing the at least one static node corresponding to the non-matching dynamic content in the first abstract syntax tree with a token that identifies the portion of the abstract syntax tree containing the non-matching dynamic content.
20. The system of claim 11 , wherein the virtual browser stores the first abstract syntax tree.