3. The computer readable storage medium of claim 2 , wherein said visual properties include, for each token, the coordinates of the token in the displayed document image, the value of the token, the DOM path of the token in the DOM tree, the type of the token, and the name of the token.
2. The computer readable storage medium of claim 1 , wherein said tokenizer for causing the computer to generate said set of tokens comprises computer executable instructions for: receiving a document in a mark-up language; rendering said document by a layout engine into a document image; extracting tokens indicative of DOM nodes with visual properties in the rendered document image; and storing said tokens in a memory with visual properties.