docs: function(matchFunction){
        if (this.matchFunction != matchFunction)
        {
          var oldMatchFunction = this.matchFunction;
          this.matchFunction = matchFunction;
  
          for (var node = this.lastChild; node; node = node.previousSibling)
            node.match(matchFunction);
  
          this.emit_matchFunctionChanged(oldMatchFunction);
        }
      }