Methods and devices for accelerating webpage rendering by a browser store document object model (DOM) tree structures and computations of rendered pages, and compare portions of a DOM tree of pages being render to determining if portions of the DOM tree structures match. If a DOM tree of a webpage to be rendered matches a DOM tree stored in memory, the computations associated with the match DOM tree may be recalled from memory, obviating the need to perform the calculations to render the page. A tree isomorphism algorithm may be used to recognize DOM trees stored in memory that match the DOM tree of the webpage to be rendered. Reusing rendering computations may significantly reducing the time and resources required for rendering web pages. Identifying reusable portions of calculation results based on DOM tree isomorphism enables the browser to reuse stored webpage rendering calculations even when URLs do not match.