René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"《编写可维护的JavaScript》读书笔记","articleBody":"## Page88 检测\n### 检测原始值\n\n``` javascript\n\b//检测字符串\nif(typeof name === \"string\"){\n}\n\n//检测数字\nif(typeof coutn === \"number\"){\n}\n\n//检测布尔值\nif(typeof found === \"boolean\" \u0026\u0026 found){\n}\n\n//检测 undefined\nif(typeof MyApp === \"undefined\"){\n}\n\n//检测 null\nvar element = document.getElementById('my_div');\nif(element !== null){\n}\n```\n### 检测在引用值\n\n``` javascript\n//检测日期\nif(value instanceof Date){\n}\n\n//检测正则表达式\nif(value instanceof RegExp){\n}\n\n//检测 Error\n\bif(value  instanceof Error){\n} \n```\n### 检测函数\n\n``` javascript\nvar myFun = function(){};\nconsole.log(typeof myFun === \"function\");\n\n/*\n  用typeof来检测函数有一个限制，在IE8和更早版本的IE浏览器中，\n  检测DOM节点中的函数都会返回“object”，而不是\"function\"\n*/\n//检测 DOM 方法\nif(\"querySelectorAll\" in document){\n}\n```\n### 检测数组\n\n``` javascript\nfunction isArray(value){\n    return Object.prototype.toString.call(value) === \"[object Array]\";\n}\n```\n### 检测属性\n\n``` javascript\nvar obj = {\n    count : 0\n};\n\nif(\"count\" in obj){\n}\n```\n","author":{"url":"https://github.com/donson","@type":"Person","name":"donson"},"datePublished":"2013-06-30T06:27:55.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/1/javascript/issues/1"}