这个组件的实现参考了log4net组件的记录方式，我们利用这个js的logger组件，就可以用log的输出的方式来进行你的调试工作了    
/*  js调试组件  */  (function () {       var logger = function (level, object, viewType) {           this.level = level;           this.object = object;           this.viewType = viewType;       }       logger.LEVEL_DEBUG = 0;       logger.LEVEL_INFO = 1;       logger.LEVEL_WARN = 2;       logger.LEVEL_ERROR = 3;       logger.LEVEL_FATAL = 4;       logger.VIEW_TYPE_ALERT = 0;       logger.VIEW_TYPE_APPEND = 1;       logger.prototype = {           setLevel: function (level) {               this.level = level;           },           setObject: function (o) {               if (typeof o == 'string') {                   this.object = document.getElementById(o);               } else {                   this.object = o;               }           },           setViewType: function (type) {               this.viewType = type;           },           log: function (s) {               this.message(100, s);           },           debug: function (s) {               this.message(logger.LEVEL_DEBUG, s);           },           info: function (s) {               this.message(logger.LEVEL_INFO, s);           },           warn: function (s) {               this.message(logger.LEVEL_WARN, s);           },           error: function (s) {               this.message(logger.LEVEL_ERROR, s);           },           fatal: function (s) {               this.message(logger.LEVEL_FATAL, s);           },           message: function (level, s) {               if (level >= this.level) {                   if (this.object != null) {                       this.object.innerHTML = s;                   } else if (this.viewType == logger.VIEW_TYPE_ALERT) {                       alert(s);                   } else {                       document.body.appendChild(document.createTextNode(s));                       document.body.appendChild(document.createElement("br"));                   }               }           }       };       if (typeof window.Logger == 'undefined' || window.Logger == null)           window.Logger = new logger(logger.LEVEL_DEBUG, null, logger.VIEW_TYPE_APPEND);   })();