nl_tokens: 高亮预览HTML的pre代码部分 highlight of preview codes
pl_tokens: function ( ) { var <mask> = this . settings ; var previewContainer = this . previewContainer ; if ( settings . previewCodeHighlight ) { previewContainer . find ( "pre" ) . addClass ( "prettyprint linenums" ) ; if ( typeof prettyPrint !== "undefined" ) { prettyPrint ( ) ; } } return this ; }