METHOD AND SYSTEM FOR THE CASCADING STYLE SHEET RULE MATCH BY USING TWO KEY SELECTORS INDEXING FOR THE RULES WITH DESCENDANT SELECTORS

摘要

A method for CSS rule match by using two selector key indexing for the rules with descendant selectors is disclosed. The method first parses various style sheets related to structured document and for each rule the rule information is stored with rightmost selector and its immediate ancestor selectors from left to right as two key�s indexes into hash table. Then the method constructs an internal document tree (DOM) representing all the elements to be displayed and creates an element pair list of the current and all its ancestor elements by traversing until root from the DOM tree. For each element in the DOM tree the CSS rule match queries the hash table to retrieve the associated style rules and then the CSS rule match searches through these styles rules to find a match or discard the rule. This reduces number of document traversal�s which improves the rendering performance. FIG. 2