1. A method for improving data accessibility, the method comprising: dividing a source document into multiple objects, in response to content of the source document; the multiple objects comprise sections and fragments, each section comprises a plurality of fragments; analyzing the multiple objects to generate multiple low level sub-trees, wherein each of the low level sub-trees is associated with a fragment and comprises the fragment; generating multiple mid-level sub-trees, wherein each of the mid-level sub-trees is associated with a unique section of the source document and comprises a link to each one of the low level sub-tree that are associated with the plurality of the fragments of the unique section; generating a top level sub-tree that comprises multiple section links, wherein each of the section links links to one of the mid-level sub-trees; creating metadata descriptive of at least one of the sub-trees generated, wherein the metadata comprises data which is not comprised in the source document; and generating a structured document that comprises the top level sub-tree, at least some of the mid- level sub-trees and at least some of the low level sub-trees, and the metadata; wherein the generating comprises writing the structured document to a tangible memory; wherein the method further comprises: retrieving one of the objects, wherein the retrieving includes acquiring from the to level sub-tree a link to a mid-level sub-tree, acquiring from the mid-level sub-tree a link to a low level sub-tree and retrieving the object from the low level sub-tree; and creating an event handler for a sub-tree wherein the event handler is included in the sub-tree; wherein the creating comprises carrying out an action which is indicated in the event handles, if an event that is indicated in the event handler occurred.
8. The method according to claim 1 , further comprising updating a sub-tree selected from a group consisting of the low level sub-trees and the mid-level sub-trees, and updating at least one sub-tree that links to the updated sub-tree, to comprise links to the updated version of the sub-tree, and to an old version of the sub-tree.