模块创建,检查工具方法（来自犀牛书）

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var Module;if (Module && (typeof Module != "object" || Module.NAME))throw new Error("Namespace 'Module' already exists");Module = {};Module.Name = 'Module';Module.Version = 0.1;Module.EXPORT = [ "require", "importSymbols" ];Module.EXPORT_OK = [ "createNamespace", "isDefined",                     "registerInitializationFunction",                     "runInitializationFunctions",                     "modules","globalNameSpace"];Module.globalNamespace = this;Module.modules = {"Module" : Module};Module.createNamespace = function(name,version){if(!name) throw new Error("Module.createNamespace(): name required");if(name.charAt(0)=='.'||   name.charAt(name.length-1)=='.'||   name.indexOf("..")!=-1)throw new Error("Module.createNamespace(): Illegal name:" + name);var parts = name.split('.');var container = Module.globalNamespace;for(var i =0; i <parts.length;i++){var part = parts[i];if(!container[part]) container[part] = {};else if(typeof container[part]!="object"){var n = parts.slice(0,i).join('.');throw new Error(n + "already exists and is not an object");}container = container[part];}var namespace = container;if(namespace.NAME) throw new Error("Module " + name + " is already defined");namespace.NAME = name;if(version) namespace.VERSION = version;Module.modules[name] = namespace;return namespace;}Module.isDefined = function(name){return name in Module.modules;}Module.require = function(name,version){if(!(name in Module.modules)){throw new Error("Module " + name + " is not defined");}if(!version) return;var n = Module.modules[name];if(!n.VERSION || n.VERSION < version){throw new Error("Module " + name + " has version " + n.VERSION + " but version " + version + "or greater is required.");}}Module.importSymbols = function(from){if(typeof from == "string") from = Module.modules[from];if(!from || typeof from !="object"){throw new Error("Module.importSymols(): " + "namespace object required");}var to = Module.globalNamespace;var symbols = [];var firstSymbol = 1;if(arguments.length>1 && typeof arguments[1] =="object"){if(arguments[1]!=null) to = arguments[1];firstSymbol = 2;}for(var a = firstSymbol; a < arguments.length; a++){symbols.push(arguments[a]);}if(symbols.length==0){if(from.EXPORT){for(var i = 0; i < from.EXPORT.length; i++){var s = from.EXPORT[i];to[s] = from[s];}return}else if(!from.EXPORT_OK){for(s in from){to[s] = from[s];return;}}}var allowed;if(from.EXPORT || from.EXPORT_OK){allowed = {};if(from.EXPORT)for(var i = 0; i < from.EXPORT.length; i++)allowed[from.EXPORT[i]] = true;if(from.EXPORT_OK)for(var i = 0; i < from.EXPORT_OK.length; i++)allowed[from.EXPORT_OK[i]] = true;}for(var i = 0; i <symbols.length; i++){var s = symbols[i];if(!(s in from)) throw new Error("Module.importSymbols(): symbol" + s +" is not defined");if(allowed && !(s in allowed)) throw new Error("Module.importSymbols(): symbol" + s +" is not public and cannot be imported.");to[s] = from[s];}}Module.registerInitializationFunction = function(f){Module._initfuncs.push(f);Module._registerEventHandler();}Module.runInitializationFunctions = function(){for(var i = 0; i < Module._initFuncs.length; i++){try{ Module._initFuncs[i](); }catch(e){/* ingore */}}Module._initFuncs.length = 0 ;}Module._initFuncs = [];Module._registerEventHandler = function(){var clientside = "window" in Module.globalNamespace && "navigator" in window;if(clientside){if(window.addEventListener){window.addEventListener("load",Module.runInitializationFunctions,false);}else if(window.attachEvent){window.attachEvent("onLoad", Module.runInitializationFunctions);}else{window.onLoad = Module.runInitializationFunctions();}}Module._registerEventHandler = function(){};}