{"id":6031,"date":"2020-04-27T18:54:53","date_gmt":"2020-04-27T10:54:53","guid":{"rendered":"https:\/\/www.lilichao.com\/?p=6031"},"modified":"2022-05-14T18:57:39","modified_gmt":"2022-05-14T10:57:39","slug":"%e5%8f%98%e9%87%8f","status":"publish","type":"post","link":"https:\/\/lilichao.com\/?p=6031","title":{"rendered":"\u53d8\u91cf"},"content":{"rendered":"\n

\u4e4b\u524d\u4ee3\u7801\u90fd\u662f\u5728\u6d4f\u89c8\u5668\u7684\u63a7\u5236\u53f0\u4e2d\u76f4\u63a5\u8fd0\u884c\u7684\uff0c\u4f46\u63a7\u5236\u53f0\u53ea\u662f\u4e34\u65f6\u6d4b\u8bd5\u7684\u624b\u6bb5\uff0c\u771f\u6b63\u5f00\u53d1\u65f6\uff0c\u524d\u7aef\u4ee3\u7801\u5fc5\u987b\u8981\u5728\u5199\u5728\u7f51\u9875\u4e2d\u3002\u5728\u7f51\u9875\u4e2d\u7f16\u5199\u4ee3\u7801\u7684\u65b9\u5f0f\u6709\u4e24\u79cd\uff1a<\/p>\n\n\n\n

\u7b2c\u4e00\u79cd\uff0c\u76f4\u63a5\u5c06js\u4ee3\u7801\u5199\u5728\u7f51\u9875\u7684script\u6807\u7b7e\u4e2d:<\/p>\n\n\n\n

\"\"
\u53ef\u4ee5\u76f4\u63a5\u5199\u5728\u5185\u90e8\u7684script\u6807\u7b7e\u4e2d<\/figcaption><\/figure>\n\n\n\n

\u7b2c\u4e8c\u79cd\uff0c\u76f4\u63a5\u5c06js\u4ee3\u7801\u7f16\u5199\u5230\u5916\u90e8\u7684js\u6587\u4ef6\u4e2d\uff0c\u7136\u540e\u901a\u8fc7script\u6807\u7b7e\u8fdb\u884c\u5f15\u5165\uff1a<\/p>\n\n\n\n

\"\"
js\u4ee3\u7801\u5199\u5728\u5916\u90e8\u7684js\u6587\u4ef6\u4e2d\uff0c\u7136\u540e\u901a\u8fc7script\u6807\u7b7e\u5f15\u5165<\/figcaption><\/figure>\n\n\n\n

console.log()<\/h2>\n\n\n\n

\u4ee3\u7801\u5728\u7f51\u9875\u4e2d\u8fd0\u884c\uff0c\u4e0d\u4f1a\u50cf\u6211\u4eec\u5728\u63a7\u5236\u53f0\u6267\u884c\u65f6\u90a3\u6837\uff0c\u81ea\u52a8\u8f93\u51fa\u7ed3\u679c\u3002\u6bd4\u5982\uff0c\u5728\u7f51\u9875\u4e2d\u76f4\u63a5\u5199\u4e00\u4e2a\u6570\u5b57100\uff0c\u5728\u7f51\u9875\u4e2d\u8fd0\u884c\u65f6\u662f\u4e0d\u4f1a\u6709\u4efb\u4f55\u7ed3\u679c\u7684\u3002<\/p>\n\n\n\n

\"\"
\u8fd9\u6837\u5199\u5728\u63a7\u5236\u53f0\u4e2d\u6ca1\u6709\u6548\u679c<\/figcaption><\/figure><\/div>\n\n\n\n

\u6240\u4ee5\u4ee3\u7801\u5199\u5728\u7f51\u9875\u4e2d\u65f6\uff0c\u5fc5\u987b\u8981\u624b\u52a8\u8c03\u7528console.log()\u65b9\u6cd5\u6765\u8f93\u51fa\u3002\u8be5\u65b9\u6cd5\u7684\u4f5c\u7528\u662f\u5728\u63a7\u5236\u53f0\u6253\u5370\u4e00\u4e2a\u5185\u5bb9\uff0c()\u4e2d\u6709\u4ec0\u4e48\uff0c\u63a7\u5236\u53f0\u5c31\u4f1a\u8f93\u51fa\u4ec0\u4e48\u3002\u8981\u5728\u63a7\u5236\u53f0\u4e2d\u6253\u5370\u4e00\u4e2a\u6570\u5b57100\uff0c\u5e94\u8be5\u4f7f\u7528console.log(100)<\/code>\u3002<\/p>\n\n\n\n

\u4ee3\u7801\uff1a<\/p>\n\n\n\n

console.log(100);<\/code><\/pre>\n\n\n\n
\u6267\u884c\u7ed3\u679c\uff1a<\/p>\n\n\n\n
\"\"
\u63a7\u5236\u53f0\u4e2d\u8f93\u51fa100<\/figcaption><\/figure><\/div>\n\n\n\n
\u7f16\u5199JS\u4ee3\u7801\u65f6\uff0c\u6309\u7167\u8bed\u6cd5\u89c4\u8303\u5e94\u8be5\u5728\u6bcf\u4e00\u6761\u8bed\u53e5\u7684\u7ed3\u5c3e\u6dfb\u52a0\u201c ; \u201d\uff0c\u4ee5\u8868\u793a\u8bed\u53e5\u7ed3\u675f\u3002\u4f46\u6d4f\u89c8\u5668\u4e2d\u5177\u6709\u81ea\u52a8\u6dfb\u52a0\u5206\u53f7\u7684\u673a\u5236\uff0c\u5982\u679c\u4f60\u61d2\u5f97\u5199\uff0c\u53ef\u4ee5\u4e0d\u5199\u3002<\/p>\n\n\n\n
\u53d8\u91cf\uff08variable\uff09<\/h2>\n\n\n\n
\u5728JS\u4e2d\u8fd9\u4e9b\u57fa\u672c\u6570\u636e\u7c7b\u578b\uff0c\u50cf\u6211\u4eec\u4e4b\u524d\u8bf4\u8fc7\u7684\u6570\u5b57\uff08number\u548cbigint\uff09\u90fd\u662f\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528\u7684\u3002console.log(100)<\/code>\u6216console.log(333n)<\/code>\u4e2d\u7684100\u548c333n\u90fd\u662f\u6570\u5b57\uff0c\u53ef\u4ee5\u76f4\u63a5\u4f5c\u4e3aconsole.log()\u7684\u53c2\u6570\u4f7f\u7528\u3002<\/p>\n\n\n\n
\u4ee3\u7801\uff1a<\/p>\n\n\n\n
console.log(100); <\/code>
console.log(333n);<\/code><\/pre>\n\n\n\n
\u6253\u5370\u8f93\u51fa\uff1a<\/p>\n\n\n\n
100\n33n<\/code><\/pre>\n\n\n\n
\u50cf100\u548c33n\u8fd9\u6837\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528\u7684\u503c\u88ab\u79f0\u4e3a\u5b57\u9762\u91cf\uff08literals\uff09\u6216\u8005\u503c\uff08value\uff09\u3002\u5728\u5b9e\u9645\u5f00\u53d1\u4e2d\u4e00\u822c\u4e0d\u4f1a\u76f4\u63a5\u4f7f\u7528\u5b57\u9762\u91cf\uff0c\u56e0\u4e3a\u5b57\u9762\u91cf\u4f7f\u7528\u8d77\u6765\u5e76\u4e0d\u65b9\u4fbf\uff0c\u4e5f\u4e0d\u4fbf\u4e8e\u7ef4\u62a4\u3002<\/p>\n\n\n\n
\u4f7f\u7528\u8d77\u6765\u4e0d\u65b9\u4fbf\u5728\u4e8e\uff0c\u4e00\u4e2a\u503c\u5728\u7a0b\u5e8f\u4e2d\u53ef\u80fd\u4f1a\u4f7f\u7528\u591a\u6b21\uff0c\u5982\u679c\u76f4\u63a5\u4f7f\u7528\u7684\u8bdd\u6211\u5fc5\u987b\u8981\u628a\u8fd9\u4e2a\u503c\u8bb0\u5f55\u4e0b\u6765\uff0c\u6bcf\u6b21\u4f7f\u7528\u90fd\u9700\u8981\u91cd\u65b0\u8f93\u5165\u975e\u5e38\u9ebb\u70e6\u3002\u5e76\u4e14\u5f53\u8fd9\u4e2a\u503c\u53d1\u751f\u53d8\u5316\u65f6\uff0c\u6211\u5fc5\u987b\u8981\u627e\u5230\u6240\u6709\u4f7f\u7528\u8be5\u503c\u7684\u5730\u65b9\uff0c\u7136\u540e\u4e00\u4e2a\u4e00\u4e2a\u7684\u4fee\u6539\u3002\u8fd9\u79cd\u4e8b\u60f3\u8d77\u6765\u5c31\u975e\u5e38\u53ef\u6015\u3002<\/p>\n\n\n\n
\u9664\u4e86\u5b57\u9762\u91cf\uff0c\u8fd8\u6709\u4e00\u79cd\u4e1c\u897f\u53eb\u505a\u53d8\u91cf\u3002\u53d8\u91cf\u5c31\u50cf\u662f\u6570\u5b66\u91cc\u8fb9\u7684x\u3001y\u3001z\u3002\u5728\u53d8\u91cf\u4e2d\u53ef\u4ee5\u5b58\u50a8\u4e0d\u540c\u7684\u503c\u3002x=3\uff0c\u6b64\u65f6x\u5c31\u8868\u793a3\u3002x=100\uff0c\u6b64\u65f6x\u5c31\u8868\u793a100\u3002\u4f7f\u7528\u53d8\u91cf\u65f6\u53ef\u4ee5\u521b\u5efa\u4e00\u4e2a\u7b80\u5355\u6613\u61c2\u7684\u53d8\u91cf\u540d\uff0c\u6bd4\u5982\uff0cage=100\u3001length=10\u3002\u8fd9\u6837\u6211\u4eec\u53ea\u9700\u8981\u77e5\u9053\u53d8\u91cf\u7684\u540d\u5b57\u5373\u53ef\u5feb\u6377\u7684\u4f7f\u7528\u503c\u3002\u540c\u65f6\u503c\u53d1\u751f\u53d8\u5316\u65f6\uff0c\u53ea\u9700\u8981\u5bf9\u53d8\u91cf\u91cd\u65b0\u8d4b\u503c\uff0c\u4e0d\u9700\u8981\u518d\u56db\u5904\u4fee\u6539\u3002<\/p>\n\n\n\n
\u5982\u4f55\u4f7f\u7528\u53d8\u91cf\uff1f<\/h3>\n\n\n\n
\u5728JS\u4e2d\u4f7f\u7528\u53d8\u91cf\uff0c\u5206\u4e3a\u4e24\u4e2a\u6b65\u9aa4\uff1a\u58f0\u660e\u548c\u8d4b\u503c\u3002<\/p>\n\n\n\n
\u58f0\u660e\u53d8\u91cf\uff1a<\/p>\n\n\n\n
let \u53d8\u91cf\u540d;<\/code><\/pre>\n\n\n\n
\u4e3a\u53d8\u91cf\u8d4b\u503c\uff1a<\/p>\n\n\n\n
\u53d8\u91cf\u540d = \u67d0\u4e2a\u503c;<\/code><\/pre>\n\n\n\n
\u58f0\u660e\u53d8\u91cf\u5c31\u76f8\u5f53\u4e8e\u6570\u5b66\u4e2d\u7684\u201c\u8bbe\u201d\u3002\u8bbex\u4e3a\u4ec0\u4e48\u4ec0\u4e48\uff0c\u8bbey\u4e3a\u4ec0\u4e48\u4ec0\u4e48\u3002\u867d\u7136\u58f0\u660e\u5e76\u4e0d\u662f\u5fc5\u987b\uff0c\u4f46\u662f\u4e0d\u5efa\u8bae\u7701\u7565\u8fd9\u4e2a\u6b65\u9aa4\u3002<\/p>\n\n\n\n
\u4f8b\u5b50\uff1a<\/p>\n\n\n\n
let a; <\/code>\/\/\u58f0\u660e\u53d8\u91cfa\n<\/code><\/em>let b; <\/code>\/\/\u58f0\u660e\u53d8\u91cfb\n<\/code><\/em>let c, d, e; <\/code>\/\/\u58f0\u660e\u53d8\u91cfc\u3001d\u548ce<\/code><\/em>\n\nconsole.log(a); <\/code>\/\/undefined\n<\/code><\/em>console.log(d); <\/code>\/\/undefined\n<\/code><\/em>console.log(f); <\/code>\/\/\u62a5\u9519<\/code><\/em> <\/code><\/pre>\n\n\n\n
\u5982\u679c\u4f7f\u7528\u6ca1\u6709\u58f0\u660e\u53d8\u91cf\uff0c\u6267\u884c\u65f6\u4f1a\u62a5\u51fa\u9519\u8bef\u4fe1\u606f\u3002<\/p>\n\n\n\n
\"\"
\u4e0a\u8ff0\u4ee3\u7801\u8fd0\u884c\u7ed3\u679c<\/figcaption><\/figure><\/div>\n\n\n\n
\u58f0\u660e\u53d8\u91cf\u4f46\u4e0d\u8d4b\u503c\u65f6\uff0c\u53d8\u91cf\u7684\u9ed8\u8ba4\u503c\u4f1a\u662fundefined\u8868\u793a\u6ca1\u6709\u8d4b\u503c\uff0c\u6211\u4eec\u58f0\u660e\u4e86a\u548cd\u4f46\u6ca1\u6709\u8d4b\u503c\uff0c\u6240\u4ee5\u6253\u5370\u65f6\u4f1a\u663e\u793aundefined\u3002\u4f46\u6253\u5370f\u65f6\uff0c\u7531\u4e8e\u6211\u4eec\u5e76\u6ca1\u6709\u5bf9\u5176\u8fdb\u884c\u58f0\u660e\uff0c\u6240\u4ee5\u4f1a\u62a5\u51fa\u9519\u8bef\u4fe1\u606f\uff1af is not defined\u3002<\/p>\n\n\n\n
\u8d4b\u503c\u64cd\u4f5c\u5c31\u975e\u5e38\u7b80\u5355\u4e86\uff0c\u5728JS\u4e2d\u53d8\u91cf\u662f\u6ca1\u6709\u7c7b\u578b\u7684\uff0c\u6240\u4ee5\u4e00\u4e2a\u53d8\u91cf\u53ef\u4ee5\u662f\u4efb\u4f55\u7684\u503c\u800c\u65e0\u9700\u8003\u8651\u7c7b\u578b\u3002\u5e76\u4e14\u5728\u4f7f\u7528\u8fc7\u7a0b\u4e2d\u53ef\u4ee5\u4efb\u610f\u4fee\u6539\u53d8\u91cf\u7684\u503c\u3002<\/p>\n\n\n\n
let a <\/code>\/\/\u58f0\u660e\u53d8\u91cfa\n<\/code><\/em>let b <\/code>\/\/\u58f0\u660e\u53d8\u91cfb\n<\/code><\/em>let c, d, e <\/code>\/\/\u58f0\u660e\u53d8\u91cfc\u3001d\u548ce\n \n<\/code><\/em>a = 10 <\/code>\/\/\u4e3aa\u8d4b\u503c10\n<\/code><\/em>b = 100n <\/code>\/\/ \u4e3ab\u8d4b\u503c100n<\/code><\/em>\nconsole.log(a) <\/code>\/\/\u8f93\u51fa\uff1a10\n<\/code><\/em>console.log(b) <\/code>\/\/\u8f93\u51fa\uff1a100n<\/code><\/em>\n\na = 30\nconsole.log(a); <\/code>\/\/\u8f93\u51fa\uff1a30<\/code><\/em> <\/code><\/pre>\n\n\n\n
\u58f0\u660e\u548c\u8d4b\u503c\u4e5f\u53ef\u4ee5\u540c\u65f6\u8fdb\u884c\uff08\u4e00\u822c\u90fd\u4f1a\u8fd9\u4e48\u505a\uff09\u3002<\/p>\n\n\n\n
let \u53d8\u91cf\u540d = \u503c<\/code><\/pre>\n\n\n\n
let a = 100\nlet b = 0b11\n \nconsole.log(a) <\/code>\/\/ \u8f93\u51fa 100<\/code><\/em>\nconsole.log(b) <\/code>\/\/ \u8f93\u51fa 3<\/code><\/em><\/pre>\n\n\n\n
\u8fd9\u79cd\u65b9\u5f0f\u4f7f\u7528\u65b9\u5f0f\u540c\u65f6\u4e5f\u975e\u5e38\u597d\u7406\u89e3let a = 100<\/code>\u76f4\u63a5\u8bfb\u53d6\u5b57\u9762\u610f\u601d\uff0c\u5c31\u662f\u8ba9a\u7b49\u4e8e100\u3002\u65e5\u5e38\u5f00\u53d1\u4e2d\u901a\u5e38\u4e5f\u662f\u58f0\u660e\u8d4b\u503c\u540c\u65f6\u8fdb\u884c\uff0c\u4e00\u6b65\u641e\u5b9a\u3002<\/p>\n\n\n\n
\u4e00\u4e2a\u53d8\u91cf\u7684\u503c\u53ef\u4ee5\u662f\u4efb\u610f\u7684\u7c7b\u578b\uff0c\u8fd9\u4e00\u70b9\u6211\u4eec\u5df2\u7ecf\u5f3a\u8c03\u8fc7\u4e86\u3002\u4f46\u662f\u53d8\u91cf\u7684\u540d\u5b57\u5374\u4e0d\u662f\u90a3\u4e48\u7684\u968f\u610f\u3002\u5728\u8bed\u8a00\u4e2d\u50cf\u53d8\u91cf\u540d\u5b57\u8fd9\u79cd\u53ef\u4ee5\u7531\u6211\u4eec\u81ea\u5df1\u5b9a\u4e49\u7684\u540d\u5b57\uff0c\u88ab\u79f0\u4e3a\u6807\u8bc6\u7b26\uff08identifier\uff09\u3002\u6807\u8bc6\u7b26\u7684\u8bbe\u7f6e\u5e76\u975e\u90a3\u4e48\u7684\u968f\u610f\uff0c\u4e3b\u8981\u8981\u6c42\u6709\u4e24\u4e2a\uff1a<\/p>\n\n\n\n
  1. \u6807\u8bc6\u7b26\u4e2d\u53ef\u4ee5\u542b\u6709\u5b57\u6bcd\u3001\u6570\u5b57\u3001\u4e0b\u5212\u7ebf\u548c$\uff0c\u4f46\u662f\u4e0d\u80fd\u4ee5\u6570\u5b57\u5f00\u5934<\/li>
  2. \u6807\u8bc6\u7b26\u4e0d\u80fd\u662fJavaScript\u4e2d\u7684\u5173\u952e\u5b57\u548c\u4fdd\u7559\u5b57<\/li>
  3. JavaScript\u4e2d\u7684\u6807\u8bc6\u7b26\u5e94\u8be5\u91c7\u7528\u9a7c\u5cf0\u547d\u540d\u6cd5\uff08\u975e\u5f3a\u5236\uff09<\/li><\/ol>\n\n\n\n
    \u7b2c\u4e00\u70b9\u597d\u7406\u89e3abc123<\/code>\u3001_abc123<\/code>\u3001$abc123<\/code>\u90fd\u662f\u6b63\u786e\u7684\uff0c\u4f46\u662f123abc\u5c31\u662f\u9519\u8bef\u7684\uff0c\u4e0d\u80fd\u4ee5\u6570\u5b57\u5f00\u5934\uff0c\u53e6\u5916$\u5f00\u5934\u4e00\u822c\u90fd\u662f\u7cfb\u7edf\u53d8\u91cf\uff0c\u6211\u4eec\u4e5f\u5e76\u4e0d\u5e38\u7528\u3002<\/p>\n\n\n\n
    \u7b2c\u4e8c\u70b9\u4e5f\u4e0d\u96be\uff0cJavaScript\u8bed\u6cd5\u4e2d\u672c\u8eab\u4e5f\u4f1a\u5360\u7528\u4e00\u4e9b\u5355\u8bcd\uff0c\u5982\uff1alet\u3001var\u3001if\u3001else\u7b49\u7b49\uff0c\u8fd9\u4e9b\u8bcd\u5728JS\u4e2d\u5b58\u5728\u6709\u7279\u6b8a\u7684\u610f\u4e49\uff0c\u6211\u4eec\u4e0d\u80fd\u4f7f\u7528\u3002\u81f3\u4e8e\u5177\u4f53\u6709\u54ea\u4e9b\uff0c\u4e0d\u592a\u9700\u8981\u5173\u5fc3\u3002\u56e0\u4e3a\u5b9e\u5728\u662f\u6709\u70b9\u591a\uff0c\u6839\u672c\u8bb0\u4e0d\u4f4f\uff0c\u597d\u5728\u8fd9\u4e9b\u8bcd\u53ea\u8981\u4f60\u6562\u7528\uff0c\u6d4f\u89c8\u5668\u4e00\u5b9a\u62a5\u9519\uff0c\u5230\u4e86\u90a3\u4e2a\u65f6\u5019\u4f60\u81ea\u7136\u5c31\u77e5\u9053\u4e86\u3002\u4e0b\u8fb9\u7684\u4ee3\u7801\u4e2d\u4f7f\u7528\u4e86\u5173\u952e\u5b57if\u4f5c\u4e3a\u53d8\u91cf\u540d\uff0c\u6267\u884c\u65f6\u6d4f\u89c8\u5668\u4f1a\u62a5\u51fa\u8bed\u6cd5\u9519\u8bef\u3002<\/p>\n\n\n\n
    let if = 100 <\/code>\/\/Uncaught SyntaxError: Unexpected token 'if'<\/code><\/em><\/pre>\n\n\n\n
    \u7b2c\u4e09\u70b9\u5e76\u4e0d\u662f\u5f3a\u5236\u7684\u89c4\u5b9a\uff0c\u800c\u662f\u4e00\u4e2a\u5f00\u53d1\u4e60\u60ef\uff0c\u5efa\u8bae\u9075\u5faa\u8fd9\u4e2a\u4e60\u60ef\u3002\u6240\u8c13\u7684\u9a7c\u5cf0\u547d\u540d\u6cd5\u6307\u7684\u662f\u540d\u5b57\u7684\u683c\u5f0f\u3002\u9a7c\u5cf0\u547d\u540d\u6cd5\u6709\u4e24\u79cd\uff1a<\/p>\n\n\n\n
    \u5c0f\u9a7c\u5cf0\u547d\u540d\u6cd5\uff1a
    \u8981\u6c42\uff1a\u9996\u5b57\u6bcd\u5c0f\u5199\uff0c\u6bcf\u4e2a\u5355\u8bcd\u5f00\u5934\u5b57\u6bcd\u5927\u5199\uff0c\u5927\u6982\u7ed3\u6784\u4e3axxxYyyZzz
    \u4f8b\u5b50\uff1amaxlength \u4fee\u6539\u4e3a\u5c0f\u9a7c\u5cf0\u5e94\u4e3a maxLength<\/p>\n\n\n\n
    \u5927\u9a7c\u5cf0\u547d\u540d\u6cd5\uff1a
    \u8981\u6c42\uff1a\u9996\u5b57\u6bcd\u5927\u5199\uff0c\u6bcf\u4e2a\u5355\u8bcd\u5f00\u5934\u5b57\u6bcd\u5927\u5199\uff0c\u5927\u6982\u7ed3\u6784\u4e3aXxxYyyZzz
    \u4f8b\u5b50\uff1amaxlength \u4fee\u6539\u4e3a\u5927\u9a7c\u5cf0 MaxLength<\/p>\n\n\n\n
    \u4e24\u79cd\u547d\u540d\u65b9\u5f0f\u90fd\u4f1a\u7528\u5230\uff0c\u5927\u90e8\u5206\u60c5\u51b5\u4e0b\u6211\u4eec\u4f1a\u4f7f\u7528\u5c0f\u9a7c\u5cf0\uff0c\u5728\u8bbe\u7f6e\u7c7b\u540d\u65f6\u4f7f\u7528\u5927\u9a7c\u5cf0\u3002\uff08\u5565\u662f\u7c7b\uff1f\u5f80\u540e\u518d\u8bf4\uff01\uff09<\/p>\n\n\n\n
    \u53d8\u91cf\u7684\u95ee\u9898<\/h3>\n\n\n\n
    \u53d8\u91cf\u7684\u4f7f\u7528\u5b66\u4f1a\u4e86\uff0c\u4ee5\u540e\u5c31\u8981\u5c3d\u91cf\u907f\u514d\u76f4\u63a5\u4f7f\u7528\u5b57\u9762\u91cf\uff08\u503c\uff09\uff0c\u800c\u662f\u5c06\u5176\u5b58\u50a8\u5230\u53d8\u91cf\u4e2d\u4f7f\u7528\u3002\u8bdd\u53c8\u8bf4\u56de\u6765\u4e86\uff0c\u53d8\u91cf\u548c\u5b57\u9762\u91cf\u4e4b\u95f4\u662f\u600e\u4e48\u8054\u7cfb\u5230\u4e00\u8d77\u7684\u5462\uff1f<\/p>\n\n\n\n
    \u8fd9\u91cc\u6211\u4eec\u5148\u8981\u505a\u4e00\u4e2a\u8bf4\u660e\uff0c\u524d\u8fb9\u6211\u8bf4\u7684\u5c06\u5b57\u9762\u91cf\u5b58\u50a8\u5230\u53d8\u91cf\u4e2d\uff0c\u8fd9\u53e5\u8bdd\u4e25\u683c\u610f\u4e49\u4e0a\u8bb2\u662f\u4e0d\u51c6\u786e\u7684\u3002<\/p>\n\n\n\n
    \u6211\u4eec\u9700\u8981\u5efa\u7acb\u4e00\u4e2a\u89c2\u5ff5\uff0c\u53d8\u91cf\u5e76\u4e0d\u80fd\u771f\u6b63\u7684\u53bb\u5b58\u50a8\u5b57\u9762\u91cf\u3002\u5728JS\u4e2d\u53d8\u91cf\u66f4\u50cf\u662f\u4e00\u4e2a\u5b57\u9762\u91cf\u7684\u522b\u540d\u3002\u5f53\u4f7f\u7528let a = 100<\/code>\u65f6\uff0c\u76f8\u5f53\u4e8e\u7ed9100\u8d77\u4e86\u4e00\u4e2a\u65b0\u7684\u540d\u5b57\u53eba\uff0c\u901a\u8fc7a\u53ef\u4ee5\u627e\u5230100\uff0c\u4ec5\u6b64\u800c\u5df2\u3002<\/p>\n\n\n\n
    \u8bb0\u4f4f\u8fd9\u53e5\u8bdd\uff0c\u53d8\u91cf\u53ea\u662f\u5b57\u9762\u91cf\u7684\u522b\u540d\uff0c\u5e76\u4e0d\u662f\u771f\u7684\u5b58\u50a8\u5b57\u9762\u91cf\u3002\u81f3\u4e8e\u5176\u4e2d\u7684\u7ec6\u8282\uff0c\u540e\u8fb9\u6211\u4eec\u518d\u6162\u6162\u7684\u5c55\u5f00\u3002<\/p>\n\n\n\n
    \u5176\u4ed6\u7684\u65b9\u5f0f<\/h3>\n\n\n\n
    \u9664\u4e86\u4f7f\u7528let\u521b\u5efa\u53d8\u91cf\uff0c\u8fd8\u6709\u5176\u4ed6\u4e24\u79cd\u65b9\u5f0f\uff1avar\u548cconst\u3002\u58f0\u660e\u53d8\u91cf\u65f6\u4e5f\u53ef\u4ee5\u4f7f\u7528var a = 100<\/code>\u6216const a = 100<\/code>\u3002<\/p>\n\n\n\n
    var\u662f\u4e00\u79cd\u53e4\u8001\u7684\u65b9\u5f0f\uff0c\u5df2\u7ecf\u4e0d\u63a8\u8350\u4f7f\u7528\u4e86\uff0c\u81f3\u4e8e\u5b83\u548clet\u7684\u533a\u522b\u540c\u6837\u8981\u653e\u5728\u540e\u8fb9\u8bf4\u660e\u3002<\/p>\n\n\n\n
    const\u58f0\u660e\u7684\u53d8\u91cf\u90fd\u662f\u5e38\u91cf\uff0c\u5e38\u91cf\u53ea\u80fd\u8d4b\u503c\u4e00\u6b21\uff0cconst a = 100<\/code> a\u7684\u503c\u5c06\u6c38\u8fdc\u662f100\u4e0d\u80fd\u4fee\u6539\uff0c\u4e00\u65e6\u4fee\u6539\u6d4f\u89c8\u5668\u5c06\u4f1a\u62a5\u51fa\u7c7b\u578b\u9519\u8bef\u3002<\/p>\n\n\n\n
    const a = 100\nconsole.log(a)\na = 200 <\/code>\/\/ Uncaught TypeError: Assignment to constant variable.<\/code><\/em><\/pre>\n\n\n\n
    \u603b\u7684\u6765\u8bb2\u8bb0\u7740\u4ee5\u4e0b\u51e0\u70b9\uff1a<\/p>\n\n\n\n
    1. \u7528\u53d8\u91cf\u4e0d\u7528\u5b57\u9762\u91cf<\/li>
    2. \u7528let\u548cconst\uff0c\u4e0d\u7528var<\/li>
    3. const\u8868\u793a\u5e38\u91cf\uff0c\u5e0c\u671b\u53d8\u91cf\u7684\u503c\u6c38\u8fdc\u4e0d\u53d8\u65f6\u624d\u4f7f\u7528<\/li><\/ol>\n","protected":false},"excerpt":{"rendered":"
      \u4e4b\u524d\u4ee3\u7801\u90fd\u662f\u5728\u6d4f\u89c8\u5668\u7684\u63a7\u5236\u53f0\u4e2d\u76f4\u63a5\u8fd0\u884c\u7684\uff0c\u4f46\u63a7\u5236\u53f0\u53ea\u662f\u4e34\u65f6\u6d4b\u8bd5\u7684\u624b\u6bb5\uff0c\u771f\u6b63\u5f00\u53d1\u65f6\uff0c\u524d\u7aef\u4ee3\u7801\u5fc5\u987b\u8981\u5728\u5199\u5728\u7f51\u9875\u4e2d\u3002 […]<\/p>\n","protected":false},"author":1,"featured_media":6036,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[241],"tags":[207,234],"_links":{"self":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/6031"}],"collection":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6031"}],"version-history":[{"count":2,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/6031\/revisions"}],"predecessor-version":[{"id":6038,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/6031\/revisions\/6038"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/media\/6036"}],"wp:attachment":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6031"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6031"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6031"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}