1. A method for extracting tabular information from a web source comprising: determining a plurality of coordinates for a plurality of visualized element nodes on the web source; determining a subset of said plurality of visualized element nodes based on said plurality of coordinates to obtain a candidate web table, wherein each of said subset of said plurality of visualized element nodes constitutes a logical cell of said candidate web table; determining textual content corresponding to said subset of said plurality of visualized element nodes as said textual content would appear after rendering said web source in a browser; and transforming said candidate web table into an explicit representation of relative spatial relation between at least one of said logical cell; and saving said explicit representation and tabular content in a structured document format.