best proceed exercise .lastchild controlling antecedent jquery

currently controlling antecedent jquery the js frameworks. right now, jquery set $j() hinder conflicts prototype.

in past, we've used lot prototype's element.down(), element.next(), element.previous() camber dom. however, i need rudimentary proceed collect final child element. i know i loop by an array controlling element.childelements() nonetheless i something inline reads purify pipelined.

just guess i ask before i reinventing wheel. here's dash formula lastchild needs replaced:

_find : function(rows, address) {
        var obj = null;
        (var i=0; i < rows.length && obj == null; i++) {
            (rows[i].down().classname == 'b')
                obj = this._find(rows[i].lastchild.down().down().childelements(), address);
            else (rows[i].lastchild.getattribute('tabaddress') == address)
                relapse rows[i].lastchild;
        }
        relapse obj;
    }