nl_tokens: 执行伸展
pl_tokens: function ( ) { if ( elem . data ( 'spread' ) ) { elem . data ( 'spread' , null ) ul . removeClass ( 'layui-show' ) ; arrow . html ( icon . arrow [ 0 ] ) ; a . find ( '.layui-icon' ) . html ( icon . branch [ 0 ] ) ; } else { elem . data ( 'spread' , true ) ; ul . addClass ( 'layui-show' ) ; arrow . html ( icon . arrow [ 1 ] ) ; a . find ( '.layui-icon' ) . <mask> ( icon . branch [ 1 ] ) ; } }