{"id":2011,"date":"2025-02-25T22:22:19","date_gmt":"2025-02-25T14:22:19","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2011"},"modified":"2025-02-25T22:22:19","modified_gmt":"2025-02-25T14:22:19","slug":"javascript-%e8%af%ad%e6%b3%95","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/02\/25\/javascript-%e8%af%ad%e6%b3%95\/","title":{"rendered":"JavaScript \u8bed\u6cd5"},"content":{"rendered":"\n<p>JavaScript \u8bed\u6cd5\u662f\u7f16\u5199 JavaScript \u7a0b\u5e8f\u7684\u89c4\u5219\u548c\u7ea6\u5b9a\u3002\u638c\u63e1 JavaScript \u8bed\u6cd5\u5bf9\u4e8e\u7406\u89e3\u548c\u7f16\u5199\u6709\u6548\u7684\u4ee3\u7801\u81f3\u5173\u91cd\u8981\u3002\u4ee5\u4e0b\u662f JavaScript \u7684\u4e00\u4e9b\u57fa\u7840\u8bed\u6cd5\u6982\u8ff0\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. <strong>\u58f0\u660e\u53d8\u91cf<\/strong><\/h3>\n\n\n\n<p>\u5728 JavaScript \u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>var<\/code>\u3001<code>let<\/code> \u548c <code>const<\/code> \u6765\u58f0\u660e\u53d8\u91cf\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">a. <strong><code>var<\/code><\/strong> (\u4f20\u7edf\u65b9\u5f0f)\uff1a<\/h4>\n\n\n\n<p><code>var<\/code> \u662f\u6700\u65e9\u7684\u58f0\u660e\u53d8\u91cf\u7684\u65b9\u5f0f\uff0c\u4f46\u5b83\u5177\u6709\u4e00\u4e9b\u4f5c\u7528\u57df\u4e0a\u7684\u95ee\u9898\uff08\u51fd\u6570\u4f5c\u7528\u57df\u800c\u975e\u5757\u7ea7\u4f5c\u7528\u57df\uff09\uff0c\u5728\u73b0\u4ee3 JavaScript \u4e2d\uff0c<code>let<\/code> \u548c <code>const<\/code> \u66f4\u5e38\u7528\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>var x = 10;\nconsole.log(x);  \/\/ \u8f93\u51fa 10<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">b. <strong><code>let<\/code><\/strong> (\u5757\u7ea7\u4f5c\u7528\u57df)\uff1a<\/h4>\n\n\n\n<p><code>let<\/code> \u58f0\u660e\u7684\u53d8\u91cf\u5177\u6709\u5757\u7ea7\u4f5c\u7528\u57df\uff0c\u53ef\u4ee5\u5728\u4ee3\u7801\u5757\u5185\u4f7f\u7528\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>let y = 20;\nif (true) {\n    let y = 30;\n    console.log(y);  \/\/ \u8f93\u51fa 30 (\u5757\u5185\u4f5c\u7528\u57df)\n}\nconsole.log(y);  \/\/ \u8f93\u51fa 20 (\u5916\u90e8\u4f5c\u7528\u57df)<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">c. <strong><code>const<\/code><\/strong> (\u5e38\u91cf)\uff1a<\/h4>\n\n\n\n<p><code>const<\/code> \u58f0\u660e\u7684\u53d8\u91cf\u662f\u5e38\u91cf\uff0c\u4e0d\u80fd\u91cd\u65b0\u8d4b\u503c\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>const z = 50;\nz = 60;  \/\/ \u9519\u8bef\uff1a\u65e0\u6cd5\u4e3a\u5e38\u91cf\u91cd\u65b0\u8d4b\u503c<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">2. <strong>\u6570\u636e\u7c7b\u578b<\/strong><\/h3>\n\n\n\n<p>JavaScript \u652f\u6301\u591a\u79cd\u6570\u636e\u7c7b\u578b\uff0c\u5206\u4e3a <strong>\u57fa\u672c\u7c7b\u578b<\/strong> \u548c <strong>\u5f15\u7528\u7c7b\u578b<\/strong>\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">a. <strong>\u57fa\u672c\u7c7b\u578b<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Number<\/strong>\uff1a\u6570\u5b57\u7c7b\u578b\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  let num = 100;<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>String<\/strong>\uff1a\u5b57\u7b26\u4e32\u7c7b\u578b\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  let str = \"Hello, World!\";<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Boolean<\/strong>\uff1a\u5e03\u5c14\u7c7b\u578b\uff0c\u8868\u793a <code>true<\/code> \u6216 <code>false<\/code>\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  let isActive = true;<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Null<\/strong>\uff1a\u8868\u793a &#8220;\u65e0&#8221; \u6216 &#8220;\u7a7a&#8221;\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  let emptyValue = null;<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Undefined<\/strong>\uff1a\u672a\u5b9a\u4e49\u7684\u503c\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  let notDefined;\n  console.log(notDefined);  \/\/ \u8f93\u51fa undefined<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Symbol<\/strong>\uff1aES6 \u65b0\u589e\u7684\u6570\u636e\u7c7b\u578b\uff0c\u7528\u4e8e\u521b\u5efa\u533f\u540d\u552f\u4e00\u7684\u503c\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  let sym = Symbol('description');<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">b. <strong>\u5f15\u7528\u7c7b\u578b<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Object<\/strong>\uff1a\u5bf9\u8c61\u7c7b\u578b\uff0c\u53ef\u4ee5\u5b58\u50a8\u591a\u4e2a\u952e\u503c\u5bf9\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  let person = { name: \"Alice\", age: 30 };<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Array<\/strong>\uff1a\u6570\u7ec4\u7c7b\u578b\uff0c\u7528\u4e8e\u5b58\u50a8\u6709\u5e8f\u7684\u6570\u636e\u96c6\u5408\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  let colors = &#91;\"red\", \"green\", \"blue\"];<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Function<\/strong>\uff1a\u51fd\u6570\u7c7b\u578b\uff0c\u7528\u4e8e\u5b9a\u4e49\u53ef\u6267\u884c\u7684\u4ee3\u7801\u5757\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  function greet() {\n      console.log(\"Hello!\");\n  }<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">3. <strong>\u8fd0\u7b97\u7b26<\/strong><\/h3>\n\n\n\n<p>JavaScript \u63d0\u4f9b\u4e86\u591a\u79cd\u8fd0\u7b97\u7b26\uff0c\u7528\u4e8e\u6267\u884c\u57fa\u672c\u64cd\u4f5c\uff0c\u5982\u6570\u5b66\u8ba1\u7b97\u3001\u6bd4\u8f83\u3001\u8d4b\u503c\u7b49\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">a. <strong>\u7b97\u672f\u8fd0\u7b97\u7b26<\/strong>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let a = 10, b = 5;\nconsole.log(a + b);  \/\/ \u52a0\u6cd5 15\nconsole.log(a - b);  \/\/ \u51cf\u6cd5 5\nconsole.log(a * b);  \/\/ \u4e58\u6cd5 50\nconsole.log(a \/ b);  \/\/ \u9664\u6cd5 2\nconsole.log(a % b);  \/\/ \u53d6\u4f59 0\nconsole.log(a++);    \/\/ \u540e\u7f6e\u9012\u589e 10\nconsole.log(++a);    \/\/ \u524d\u7f6e\u9012\u589e 12<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">b. <strong>\u6bd4\u8f83\u8fd0\u7b97\u7b26<\/strong>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>console.log(10 &gt; 5);   \/\/ true\nconsole.log(10 &lt; 5);   \/\/ false\nconsole.log(10 == 10); \/\/ true (\u76f8\u7b49)\nconsole.log(10 === \"10\"); \/\/ false (\u4e25\u683c\u76f8\u7b49)\nconsole.log(10 != 5);  \/\/ true (\u4e0d\u7b49)\nconsole.log(10 !== \"10\"); \/\/ true (\u4e25\u683c\u4e0d\u7b49)<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">c. <strong>\u903b\u8f91\u8fd0\u7b97\u7b26<\/strong>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let x = true, y = false;\nconsole.log(x &amp;&amp; y);  \/\/ false (\u4e0e\u8fd0\u7b97)\nconsole.log(x || y);  \/\/ true  (\u6216\u8fd0\u7b97)\nconsole.log(!x);      \/\/ false (\u975e\u8fd0\u7b97)<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">d. <strong>\u8d4b\u503c\u8fd0\u7b97\u7b26<\/strong>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let z = 5;\nz += 10;  \/\/ z = z + 10\uff0cz \u73b0\u5728\u4e3a 15\nz -= 5;   \/\/ z = z - 5\uff0cz \u73b0\u5728\u4e3a 10<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">4. <strong>\u63a7\u5236\u7ed3\u6784<\/strong><\/h3>\n\n\n\n<p>\u63a7\u5236\u7ed3\u6784\u7528\u4e8e\u6839\u636e\u6761\u4ef6\u5224\u65ad\u6267\u884c\u4e0d\u540c\u7684\u4ee3\u7801\u5757\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">a. <strong>if \u8bed\u53e5<\/strong>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let age = 18;\nif (age &gt;= 18) {\n    console.log(\"You are an adult.\");\n} else {\n    console.log(\"You are a minor.\");\n}<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">b. <strong>switch \u8bed\u53e5<\/strong>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let day = 2;\nswitch (day) {\n    case 1:\n        console.log(\"Monday\");\n        break;\n    case 2:\n        console.log(\"Tuesday\");\n        break;\n    default:\n        console.log(\"Invalid day\");\n}<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">c. <strong>\u5faa\u73af\u8bed\u53e5<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>for \u5faa\u73af<\/strong>\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  for (let i = 0; i &lt; 5; i++) {\n      console.log(i);  \/\/ \u8f93\u51fa 0 1 2 3 4\n  }<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>while \u5faa\u73af<\/strong>\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  let i = 0;\n  while (i &lt; 5) {\n      console.log(i);  \/\/ \u8f93\u51fa 0 1 2 3 4\n      i++;\n  }<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>do\u2026while \u5faa\u73af<\/strong>\uff1a<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>  let i = 0;\n  do {\n      console.log(i);  \/\/ \u8f93\u51fa 0 1 2 3 4\n      i++;\n  } while (i &lt; 5);<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">5. <strong>\u51fd\u6570<\/strong><\/h3>\n\n\n\n<p>\u51fd\u6570\u7528\u4e8e\u5c01\u88c5\u4ee3\u7801\u5757\uff0c\u4ee5\u4fbf\u91cd\u590d\u4f7f\u7528\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">a. <strong>\u58f0\u660e\u51fd\u6570<\/strong>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>function greet() {\n    console.log(\"Hello, World!\");\n}\n\ngreet();  \/\/ \u8c03\u7528\u51fd\u6570<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">b. <strong>\u51fd\u6570\u53c2\u6570\u4e0e\u8fd4\u56de\u503c<\/strong>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>function add(a, b) {\n    return a + b;\n}\n\nlet result = add(5, 3);\nconsole.log(result);  \/\/ \u8f93\u51fa 8<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">c. <strong>\u533f\u540d\u51fd\u6570\uff08\u51fd\u6570\u8868\u8fbe\u5f0f\uff09<\/strong>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let multiply = function(a, b) {\n    return a * b;\n};\nconsole.log(multiply(2, 3));  \/\/ \u8f93\u51fa 6<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">d. <strong>\u7bad\u5934\u51fd\u6570<\/strong>\uff1a<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>let divide = (a, b) =&gt; a \/ b;\nconsole.log(divide(10, 2));  \/\/ \u8f93\u51fa 5<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">6. <strong>\u5bf9\u8c61\u4e0e\u6570\u7ec4<\/strong><\/h3>\n\n\n\n<p>JavaScript \u4e2d\u7684\u5bf9\u8c61\u548c\u6570\u7ec4\u662f\u5e38\u89c1\u7684\u5f15\u7528\u7c7b\u578b\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">a. <strong>\u5bf9\u8c61<\/strong><\/h4>\n\n\n\n<p>\u5bf9\u8c61\u662f\u7531\u591a\u4e2a\u952e\u503c\u5bf9\u7ec4\u6210\u7684\u96c6\u5408\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>let person = { name: \"Alice\", age: 25 };\nconsole.log(person.name);  \/\/ \u8f93\u51fa Alice<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\">b. <strong>\u6570\u7ec4<\/strong><\/h4>\n\n\n\n<p>\u6570\u7ec4\u662f\u6709\u5e8f\u7684\u6570\u636e\u96c6\u5408\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>let fruits = &#91;\"apple\", \"banana\", \"cherry\"];\nconsole.log(fruits&#91;0]);  \/\/ \u8f93\u51fa apple<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u5c0f\u7ed3<\/h3>\n\n\n\n<p>JavaScript \u8bed\u6cd5\u5305\u62ec\u4e86\u53d8\u91cf\u58f0\u660e\u3001\u6570\u636e\u7c7b\u578b\u3001\u8fd0\u7b97\u7b26\u3001\u63a7\u5236\u7ed3\u6784\u3001\u51fd\u6570\u4ee5\u53ca\u5bf9\u8c61\u548c\u6570\u7ec4\u7b49\u91cd\u8981\u6982\u5ff5\u3002\u638c\u63e1\u8fd9\u4e9b\u57fa\u672c\u8bed\u6cd5\uff0c\u53ef\u4ee5\u5e2e\u52a9\u4f60\u66f4\u9ad8\u6548\u5730\u7f16\u5199 JavaScript \u4ee3\u7801\u3002\u901a\u8fc7\u4e0d\u65ad\u5b9e\u8df5\u548c\u5b66\u4e60\uff0c\u4f60\u4f1a\u66f4\u52a0\u719f\u6089 JavaScript \u7684\u5404\u79cd\u7279\u6027\u548c\u6280\u5de7\u3002<\/p>\n\n\n\n<p>\u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>JavaScript \u8bed\u6cd5\u662f\u7f16\u5199 JavaScript \u7a0b\u5e8f\u7684\u89c4\u5219\u548c\u7ea6\u5b9a\u3002\u638c\u63e1 JavaScript \u8bed\u6cd5\u5bf9\u4e8e [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[46],"tags":[],"class_list":["post-2011","post","type-post","status-publish","format-standard","hentry","category-javascript"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2011","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=2011"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2011\/revisions"}],"predecessor-version":[{"id":2012,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2011\/revisions\/2012"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2011"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2011"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2011"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}