nl_tokens: - parentNode 仅筛选此节点下的节点 .
pl_tokens: function _getElement ( name , parentNode ) { if ( name === '' ) name = null ; var _elem ; var _isarr = false ; if ( typeof name === 'string' ) { if ( name [ 0 ] == '<' ) { _elem = window . document . createElement ( 'div' ) ; _elem . innerHTML = name ; if ( _elem . childNodes . length == 1 ) { _elem = _elem . childNodes [ 0 ] ; _isarr = false ; } else { _elem = _elem . childNodes ; _isarr = true ; } } else { if ( name . indexOf ( '<' ) > 0 || name . indexOf ( '>' ) > 0 ) throw new Error ( 'Syntax error, unrecognized' ) ; var names = name . split ( ' ' ) ; var nodes = parentNode ? [ parentNode ] : null ; for ( var i = 0 ; i < names . length ; i ++ ) { if ( names [ i ] != '' ) nodes = _matchElement ( nodes , names [ i ] , ! ! parentNode ) ; } if ( nodes . length <= 1 ) { _elem = nodes [ 0 ] ; _isarr = false ; } else { _elem = nodes ; _isarr = true ; } } } else { _elem = <mask> ; } return { _elem , _isarr } ; }