{"id":6093,"date":"2020-05-03T19:31:33","date_gmt":"2020-05-03T11:31:33","guid":{"rendered":"https:\/\/www.lilichao.com\/?p=6093"},"modified":"2022-05-14T19:59:45","modified_gmt":"2022-05-14T11:59:45","slug":"if%e8%af%ad%e5%8f%a5","status":"publish","type":"post","link":"https:\/\/lilichao.com\/?p=6093","title":{"rendered":"if\u8bed\u53e5"},"content":{"rendered":"\n

if\u8bed\u53e5\u4e5f\u79f0\u4e3a\u6761\u4ef6\u5224\u65ad\u8bed\u53e5\u3002\u901a\u8fc7if\u8bed\u53e5\u53ef\u4ee5\u4e3a\u8bed\u53e5\u7684\u6267\u884c\u8bbe\u7f6e\u4e00\u4e9b\u6761\u4ef6\uff0c\u6761\u4ef6\u6ee1\u8db3\u65f6\u8bed\u53e5\u6267\u884c\uff0c\u5426\u5219\u8bed\u53e5\u4e0d\u6267\u884c\u3002<\/p>\n\n\n\n

\u8bed\u6cd5\u4e00<\/p>\n\n\n\n

if(\u6761\u4ef6\u8868\u8fbe\u5f0f){
    \u8bed\u53e5
}<\/code><\/pre>\n\n\n\n
\u8fd9\u662f\u6700\u7b80\u5355\u7684if\u8bed\u53e5\uff0c\u5728if\u540e\u7684()\u4e2d\u8bbe\u7f6e\u4e86\u6761\u4ef6\u8868\u8fbe\u5f0f\u3002\u6761\u4ef6\u8868\u8fbe\u5f0f\u6700\u7ec8\u4f1a\u88ab\u8ba1\u7b97\u4e3a\u4e00\u4e2a\u5e03\u5c14\u503c\uff08true\u6216false\uff09\uff0c\u5982\u679c\u503c\u4e3atrue\u5219\u6267\u884c\u5176\u540e\u7684\u8bed\u53e5\uff0c\u5982\u679c\u503c\u4e3afalse\u5219\u4e0d\u4f1a\u6267\u884c\u3002<\/p>\n\n\n\n
\u793a\u4f8b\uff1a<\/p>\n\n\n\n
if (true) {
    console.log('\u6761\u4ef6\u8868\u8fbe\u5f0f\u4e3atrue\uff0c\u8bed\u53e5\u4f1a\u6267\u884c')
}<\/code><\/pre>\n\n\n\n
\u4e0a\u4f8b\u4e2d\uff0cif\u540e\u7684\u6761\u4ef6\u8868\u8fbe\u5f0f\u5c31\u662ftrue\uff0c\u6240\u4ee5\u8fd0\u7b97\u7ed3\u679c\u4e5f\u662ftrue\uff0c\u8bed\u53e5\u6700\u7ec8\u4f1a\u6267\u884c\uff0c\u5728\u63a7\u5236\u53f0\u4e2d\u4f1a\u770b\u5230\u6253\u5370\u8bed\u53e5\u7684\u8f93\u51fa\u3002<\/p>\n\n\n\n
\u793a\u4f8b\uff1a<\/p>\n\n\n\n
if (false) {
    console.log('\u6761\u4ef6\u8868\u8fbe\u5f0f\u4e3afalse\uff0c\u8bed\u53e5\u4f1a\u6267\u884c')
}<\/code><\/pre>\n\n\n\n
\u4e0a\u4f8b\u4e2d\uff0cif\u540e\u7684\u6761\u4ef6\u8868\u8fbe\u5f0f\u662ffalse\uff0c\u8bed\u53e5\u6700\u7ec8\u4e0d\u4f1a\u6267\u884c\uff0c\u63a7\u5236\u53f0\u4e0d\u4f1a\u770b\u5230\u4efb\u4f55\u8f93\u51fa\u3002<\/p>\n\n\n\n
\u9664\u6b64\u4e4b\u5916\uff0c\u5982\u679c\u5728\u6761\u4ef6\u8868\u8fbe\u5f0f\u4e2d\u4f20\u9012\u7684\u5e76\u4e0d\u662f\u4e00\u4e2a\u5e03\u5c14\u503c\uff0c\u6bd4\u5982\u8fd9\u6837\uff1a<\/p>\n\n\n\n
if ('hello'){
    console.log('\u4f1a\u4e0d\u4f1a\u6267\u884c\u5462\uff1f')
}<\/code><\/pre>\n\n\n\n
\u4e0a\u4f8b\u4e2d\uff0c\u6761\u4ef6\u8868\u8fbe\u5f0f\u4f20\u9012\u7684\u662f\u4e00\u4e2a\u5b57\u7b26\u4e32’hello’\uff0c\u6761\u4ef6\u8868\u8fbe\u5f0f\u6700\u7ec8\u90fd\u4f1a\u8f6c\u6362\u4e3a\u5e03\u5c14\u503c\uff0c\u800c’hello’\u662f\u4e00\u4e2a\u975e\u7a7a\u5b57\u7b26\u4e32\uff0c\u6240\u4ee5\u8fd9\u91cc\u5b83\u4f1a\u88ab\u8f6c\u6362\u4e3atrue\uff0c\u6240\u4ee5\u4ee3\u7801\u4f9d\u7136\u53ef\u4ee5\u6267\u884c\u3002<\/p>\n\n\n\n
\u7c7b\u4f3c\u4e0a\u4f8b\u4e2d\uff0c\u76f4\u63a5\u5728\u6761\u4ef6\u8868\u8fbe\u5f0f\u4e2d\u5199\u503c\u7684\u60c5\u51b5\u5e76\u4e0d\u591a\u3002\u56e0\u4e3a\u4e00\u65e6\u76f4\u63a5\u5c06\u503c\u5199\u5728\u6761\u4ef6\u8868\u8fbe\u5f0f\u4e0a\uff0c\u90a3\u4e48\u5b83\u7684\u6700\u7ec8\u503c\u5c31\u5df2\u7ecf\u786e\u5b9a\uff0c\u503c\u4e00\u65e6\u786e\u5b9a\u90a3\u4e48\u6240\u8c13\u7684\u903b\u8f91\u5224\u65ad\u4e5f\u5c31\u6ca1\u6709\u4ec0\u4e48\u610f\u4e49\u4e86\uff0c\u6240\u4ee5\u4e00\u822c\u6761\u4ef6\u8868\u8fbe\u5f0f\u5904\u4f1a\u8bbe\u7f6e\u53d8\u91cf\uff0c\u6216\u8005\u662f\u4e00\u4e9b\u7531\u53d8\u91cf\u7684\u7ec4\u6210\u7684\u8868\u8fbe\u5f0f\u3002\u6bd4\u5982\u8fd9\u6837\uff1a<\/p>\n\n\n\n
\u6761\u4ef6\u8868\u8fbe\u5f0f\u793a\u4f8b\uff1a
    a > 10  \/\/ \u5f53a\u5927\u4e8e10\u65f6\uff0c\u8fd4\u56detrue<\/code>
    a > 10 && a < 20 \/\/ \u5f53a\u5927\u4e8e10\u4e14\u5c0f\u4e8e20\u65f6\uff0c\u8fd4\u56detrue<\/code>
    a > 10 || a < 5 \/\/ \u5f53a\u5927\u4e8e10\u6216a\u5c0f\u4e8e5\u65f6\uff0c\u8fd4\u56detrue<\/code><\/p>\n\n\n\n
\u793a\u4f8b\uff1a<\/p>\n\n\n\n
if (a > 10) {
    console.log('a\u6bd410\u8981\u5927')
}<\/code><\/pre>\n\n\n\n
\u8fd9\u6837\u4e00\u6765\uff0c\u8bed\u53e5\u6267\u884c\u4e0e\u5426\u5c06\u4f1a\u7531a\u7684\u503c\u6765\u51b3\u5b9a\uff0ca\u5927\u4e8e10\u90a3\u4e48\u8bed\u53e5\u5c31\u4f1a\u6267\u884c\uff0ca\u4e0d\u5927\u4e8e10\uff0c\u8bed\u53e5\u5c31\u4e0d\u4f1a\u6267\u884c\u3002<\/p>\n\n\n\n
\u4ee3\u7801\u5757<\/h2>\n\n\n\n
\u8fd9\u91ccif\u540e\u7684{}\u88ab\u79f0\u4e3a\u4ee3\u7801\u5757\uff0c\u5728JS\u4e2d\u4ee3\u7801\u5757\u7528\u6765\u4e3a\u4ee3\u7801\u5206\u7ec4\uff0c\u5728\u540c\u4e00\u4ee3\u7801\u5757\u4e2d\u7684\u4ee3\u7801\u5c5e\u4e8e\u540c\u4e00\u7ec4\u3002<\/p>\n\n\n\n
{    \n    console.log('a\u6bd410\u8981\u5927')\n}<\/code><\/pre>\n\n\n\n
\u4e0a\u4f8b\u5c31\u662f\u4e00\u4e2a\u4ee3\u7801\u5757\uff0c\u5728if\u8bed\u53e5\u4e2d\uff0c\u5982\u679c\u6761\u4ef6\u8868\u8fbe\u5f0f\u4e3atrue\uff0c\u5219\u4ee3\u7801\u5757\u4e2d\u7684\u4ee3\u7801\u5c06\u4f1a\u81ea\u4e0a\u5411\u4e0b\u4f9d\u6b21\u6267\u884c\uff0c\u5982\u679c\u6761\u4ef6\u8868\u8fbe\u5f0f\u4e3afalse\uff0c\u5219\u4ee3\u7801\u5757\u4e2d\u7684\u4ee3\u7801\u5c06\u4e0d\u4f1a\u6267\u884c\u3002<\/p>\n\n\n\n
\u76ee\u524d\uff0c\u6211\u4eec\u5199\u7684if\u8bed\u53e5\u90fd\u6bd4\u8f83\u7b80\u5355\uff0c\u4ee3\u7801\u5757\u4e2d\u53ea\u6709\u4e00\u884c\u4ee3\u7801\uff0c\u5176\u5b9e\u4e5f\u662f\u53ef\u4ee5\u5199\u591a\u884c\u7684\u3002<\/p>\n\n\n\n
if (a > 10) {    <\/code>\n    console.log('a\u6bd410\u8981\u5927')<\/code>\n    console.log('1111111')<\/code>\n    console.log('2222222')<\/code>\n}<\/code><\/pre>\n\n\n\n
\u4e0a\u8fb9\u4ee3\u7801\u5757\u4e2d\u5305\u542b\u4e09\u884c\u4ee3\u7801\uff0c\u8fd9\u4e09\u884c\u4ee3\u7801\u8981\u4e48\u90fd\u6267\u884c\uff0c\u8981\u4e48\u90fd\u4e0d\u6267\u884c\uff0c\u7531if\u540e\u7684\u6761\u4ef6\u8868\u8fbe\u5f0f\u51b3\u5b9a\u3002<\/p>\n\n\n\n
\u5982\u679cif\u540e\u53ea\u6709\u4e00\u6761\u8bed\u53e5\uff0c\u50cf\u8fd9\u6837\u7684\uff1a<\/p>\n\n\n\n
if ('hello'){    \n    console.log('\u4f1a\u4e0d\u4f1a\u6267\u884c\u5462\uff1f')\n}<\/code><\/pre>\n\n\n\n
\u8fd9\u91cc\u7684{}\u53ef\u4ee5\u7701\u7565\u4e0d\u5199<\/p>\n\n\n\n
if ('hello')<\/code>\n    console.log('\u4f1a\u4e0d\u4f1a\u6267\u884c\u5462\uff1f')<\/code><\/pre>\n\n\n\n
\u8fd9\u4e24\u79cd\u5199\u6cd5\u7684\u6548\u679c\u662f\u4e00\u6837\u7684\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
if\u8bed\u53e5\u4e5f\u79f0\u4e3a\u6761\u4ef6\u5224\u65ad\u8bed\u53e5\u3002\u901a\u8fc7if\u8bed\u53e5\u53ef\u4ee5\u4e3a\u8bed\u53e5\u7684\u6267\u884c\u8bbe\u7f6e\u4e00\u4e9b\u6761\u4ef6\uff0c\u6761\u4ef6\u6ee1\u8db3\u65f6\u8bed\u53e5\u6267\u884c\uff0c\u5426\u5219\u8bed\u53e5\u4e0d\u6267\u884c\u3002 \u8bed […]<\/p>\n","protected":false},"author":1,"featured_media":6147,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[241],"tags":[248,200,234,249],"_links":{"self":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/6093"}],"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=6093"}],"version-history":[{"count":2,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/6093\/revisions"}],"predecessor-version":[{"id":6095,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/posts\/6093\/revisions\/6095"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=\/wp\/v2\/media\/6147"}],"wp:attachment":[{"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6093"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6093"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lilichao.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6093"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}