How to change only the fill color style of the layer

function ftn1() {

  function cTID(s) { return app.charIDToTypeID(s); };

  function sTID(s) { return app.stringIDToTypeID(s); };

    var desc4 = new ActionDescriptor();

        var ref2 = new ActionReference();

        ref2.putProperty( cTID('Prpr'), cTID('Lefx') );

        ref2.putEnumerated( cTID('Lyr '), cTID('Ordn'), cTID('Trgt') );

    desc4.putReference( cTID('null'), ref2 );

        var desc5 = new ActionDescriptor();

        desc5.putUnitDouble( cTID('Scl '), cTID('#Prc'), 100.000000 );

            var desc6 = new ActionDescriptor();

            desc6.putBoolean( cTID('enab'), true );

            desc6.putEnumerated( cTID('Md  '), cTID('BlnM'), cTID('Nrml') );

            desc6.putUnitDouble( cTID('Opct'), cTID('#Prc'), 100.000000 );

                var desc7 = new ActionDescriptor();

                desc7.putDouble( cTID('Rd  '), 129.001923 );

                desc7.putDouble( cTID('Grn '), 129.001923 );

                desc7.putDouble( cTID('Bl  '), 129.001923 );

            desc6.putObject( cTID('Clr '), cTID('RGBC'), desc7 );

        desc5.putObject( cTID('SoFi'), cTID('SoFi'), desc6 );

    desc4.putObject( cTID('T   '), cTID('Lefx'), desc5 );

    executeAction( cTID('setd'), desc4, DialogModes.NO );

};

This code change current layer styles, i want to change only fill color style.

Other style must not change. Maybe you help me with manual for ActionDescriptor() or some samples.

Sorry for my english.