{"author_url":"https://blog.hatena.ne.jp/mindcat/","version":"1.0","description":"\u306f\u3058\u3081\u306b JavaScript\u306e\u521d\u5fc3\u8005\u306b\u3068\u3063\u3066undefined\u3068\u3044\u3046\u306e\u306f\u3061\u3087\u3063\u3068\u6df7\u4e71\u3092\u62db\u304f\u3082\u306e\u3089\u3057\u3044\u3002null\u3068\u306e\u9055\u3044\u3084\u4f7f\u3044\u5206\u3051\u304c\u3088\u304f\u5206\u304b\u3089\u306a\u304b\u3063\u305f\u308a\u3001\u6570\u5024\u3084\u30d6\u30fc\u30eb\u5024\u3068\u306e\u6bd4\u8f03\u304c\u4e0d\u81ea\u7136\u3060\u3063\u305f\u308a\u3059\u308b\u306e\u304c\u539f\u56e0\u3068\u601d\u308f\u308c\u308b\u3002\u3053\u3053\u3067\u306f\u3001\u305d\u306e\u3088\u3046\u306aundefined\u306e\u3044\u308d\u3044\u308d\u306b\u3064\u3044\u3066\u307e\u3068\u3081\u3066\u307f\u305f\u3002 ECMA262\u898f\u683c\u3067\u306f undefined\u3068null\u306b\u95a2\u3057\u3066\u3001ECMA262\u898f\u683c\u3067\u306f\u6700\u521d\u306b\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u8a18\u8ff0\u304c\u3042\u308b\u3002 4.3.9 undefined value primitive value used when a variable has not been assigned a value. 4.3.11 n\u2026","author_name":"mindcat","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fmindcat.hatenadiary.org%2Fentry%2F20100512%2F1273683917\" title=\"JavaScript\u306eundefined\u3068\u3044\u3046\u30af\u30bb\u8005\u306e\u3044\u308d\u3044\u308d - \u98a8\u3068\u5b87\u5b99\u3068\u30d7\u30ed\u30b0\u30e9\u30e0\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","title":"JavaScript\u306eundefined\u3068\u3044\u3046\u30af\u30bb\u8005\u306e\u3044\u308d\u3044\u308d","blog_url":"https://mindcat.hatenadiary.org/","url":"https://mindcat.hatenadiary.org/entry/20100512/1273683917","blog_title":"\u98a8\u3068\u5b87\u5b99\u3068\u30d7\u30ed\u30b0\u30e9\u30e0","image_url":null,"provider_url":"https://hatena.blog","type":"rich","published":"2010-05-12 02:05:17","height":"190","width":"100%","categories":["JavaScript"],"provider_name":"Hatena Blog"}