{"id":159,"date":"2021-02-26T00:52:27","date_gmt":"2021-02-25T16:52:27","guid":{"rendered":"https:\/\/www.52dixiaowo.com\/javascript\/?p=159"},"modified":"2021-02-26T00:52:29","modified_gmt":"2021-02-25T16:52:29","slug":"js-%e4%b8%ad%e7%9a%84-typeof-%e5%88%a4%e6%96%ad%e6%95%b0%e6%8d%ae%e7%b1%bb%e5%9e%8b","status":"publish","type":"post","link":"https:\/\/www.52dixiaowo.com\/javascript\/post-159.html","title":{"rendered":"Js \u4e2d\u7684 typeof \u5224\u65ad\u6570\u636e\u7c7b\u578b"},"content":{"rendered":"\n<p>\u5728 Js \u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528 typeof \u5173\u952e\u5b57\u5224\u65ad\u5bf9\u6570\u636e\u7c7b\u578b\u8fdb\u884c\u5224\u65ad<\/p>\n\n\n\n<p>1.\u5224\u65ad\u4e00\u4e0b number \u7c7b\u578b<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var num1 = 1;\nvar num2 = 1.2;\nvar num3 = NaN;\n\/\/\u628a\u4e0a\u9762\u4e09\u4e2a\u6570\u636e\u53ca\u5176\u7c7b\u578b\u8f93\u51fa\u5230\u9875\u9762\u4e0a\ndocument.write(num+\"--\"+typeof(num1)+\"&lt;br\/>\");\ndocument.write(num+\"--\"+typeof(num2)+\"&lt;br\/>\");\ndocument.write(num+\"--\"+typeof(num3)+\"&lt;br\/>\");<\/code><\/pre>\n\n\n\n<p>2.\u5224\u65ad\u4e00\u4e0b string \u7c7b\u578b<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var str1 = \"abc\";\nvar str2 = 'def';\ndocument.write(str1+\"--\"+typeof(str1)+\"&lt;br\/>\");\ndocument.write(str2+\"--\"+typeof(str2)+\"&lt;br\/>\");<\/code><\/pre>\n\n\n\n<p>3.\u5224\u65ad\u4e00\u4e0b boolean \u7c7b\u578b<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var flag1 = true;\nvar flag2 = false;\ndocument.write(flag1+\"--\"+typeof(flag1)+\"&lt;br\/>\");\ndocument.write(flag2+\"--\"+typeof(flag2)+\"&lt;br\/>\");<\/code><\/pre>\n\n\n\n<p>4.\u5224\u65ad null <\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var obj = null;\ndocuemnt.write(obj+\"--\"+typeof(obj)+\"&lt;br\/>\");<\/code><\/pre>\n\n\n\n<p>5.\u5224\u65ad undefined<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var un1 =undefined;\nvar un2;  \/\/\u8fd9\u4e2a\u4e0d\u8d4b\u503c\ndocument.write(un1+\"--\"+typeof(un1)+\"&lt;br\/>\");\ndocument.write(un2+\"--\"+typeof(un2)+\"&lt;br\/>\");<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u5728 Js \u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528 typeof \u5173\u952e\u5b57\u5224\u65ad\u5bf9\u6570\u636e\u7c7b\u578b\u8fdb\u884c\u5224\u65ad 1.\u5224\u65ad\u4e00\u4e0b number \u7c7b\u578b 2.\u5224\u65ad&hellip; <a href=\"https:\/\/www.52dixiaowo.com\/javascript\/post-159.html\" class=\"more-link\">\u7ee7\u7eed\u9605\u8bfb <span class=\"screen-reader-text\">Js \u4e2d\u7684 typeof \u5224\u65ad\u6570\u636e\u7c7b\u578b<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[6],"tags":[],"_links":{"self":[{"href":"https:\/\/www.52dixiaowo.com\/javascript\/wp-json\/wp\/v2\/posts\/159"}],"collection":[{"href":"https:\/\/www.52dixiaowo.com\/javascript\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.52dixiaowo.com\/javascript\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/javascript\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/javascript\/wp-json\/wp\/v2\/comments?post=159"}],"version-history":[{"count":1,"href":"https:\/\/www.52dixiaowo.com\/javascript\/wp-json\/wp\/v2\/posts\/159\/revisions"}],"predecessor-version":[{"id":160,"href":"https:\/\/www.52dixiaowo.com\/javascript\/wp-json\/wp\/v2\/posts\/159\/revisions\/160"}],"wp:attachment":[{"href":"https:\/\/www.52dixiaowo.com\/javascript\/wp-json\/wp\/v2\/media?parent=159"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/javascript\/wp-json\/wp\/v2\/categories?post=159"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.52dixiaowo.com\/javascript\/wp-json\/wp\/v2\/tags?post=159"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}