js基础
Posted 北方姆Q
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1.滚动条
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 <div id="i1" style="background-color: pink;color: white;display: inline-block">北方姆Q</div> 9 <script> 10 setInterval(‘f1()‘, 1000); 11 function f1() { 12 var tag = document.getElementById(‘i1‘); 13 var test = tag.innerText; 14 var a = test.charAt(0); 15 var sub = test.substring(1, test.length); 16 var new_str = sub + a; 17 tag.innerText = new_str; 18 } 19 </script> 20 </body> 21 </html>
2.
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 <script> 9 // 序列化 10 var d1 = {‘k1‘: v1, ‘k2‘: v2}; 11 var s1 = JSON.stringify(d1); 12 var d2 = JSON.parse(s1); 13 // 转义url中未转移的字符 14 var url = "https://www.baidu.com/s?wd=%E5%8C%97%E6%96%B9%E5%A7%86q&rsv_spt=1&rsv_iqid=0xebeece360003cc9c&issp=1&f=3&rsv_bp=0&rsv_idx=2&ie=utf-8&tn=baiduhome_pg&rsv_enter=1&rsv_sug3=1&rsv_sug1=1&rsv_sug7=001&rsv_sug2=1&rsp=3&rsv_sug9=es_2_1&rsv_sug4=1549&rsv_sug=9"; 15 var ret1 = encodeURI(url); 16 var u1 = decodeURI(ret); 17 // 转义url组件中未转移的字符 18 var ret2 = encodeURIComponent(url); 19 var u2 = decodeURIComponent(ret2); 20 // 时间处理 21 d = new Date(); 22 d.getDate(); 23 d.getUTCDay(); 24 d.setDate(d.getDate()+3); 25 </script> 26 </body> 27 </html>
3.
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 <script> 9 if (1 === ‘1‘){ 10 XXXXXXX; 11 } 12 else if (1 === 1){ 13 XXXXXXX; 14 } 15 else { 16 XXXXXXX; 17 } 18 19 20 switch (name){ 21 case ‘1‘: 22 age = 123; 23 break; 24 case ‘2‘: 25 age = 456; 26 break; 27 default: 28 age = 888; 29 break 30 } 31 32 33 while (1 === 1){ 34 XXXXXXX; 35 break; 36 XXXXXXX; 37 continue; 38 } 39 40 41 var names = [‘bfmq‘, ‘dfmq‘, ‘nfmq‘, ‘xfmq‘]; 42 for(var i = 0;i <names.length;i++){ 43 console.log(i); 44 console.log(names[i]); 45 } 46 47 48 var names = {‘bfmq‘: 18, ‘dfmq‘: 18}; 49 for(var index in names){ 50 console.log(i); 51 console.log(names[i]); 52 } 53 54 55 try{ 56 // 执行try中的代码 57 } 58 catch (e){ 59 // 如果捕获到了e错误，则执行这里的代码 60 } 61 finally { 62 // 最后不论怎么样都会执行的代码 63 } 64 // 主动丢出异常 65 throw new Error(‘wtf‘) 66 </script> 67 </body> 68 </html>
4.函数分类
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 <script> 9 // 普通函数 10 function f1(arg) { 11 alert(arg); 12 } 13 // 自执行函数 14 (function (arg) { 15 alert(arg); 16 })(123); 17 // 匿名函数 18 setInterval(function () { 19 alert(123); 20 }, 1000) 21 </script> 22 </body> 23 </html>
5.闭包
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 <script> 9 (function () { 10 var a = 123; 11 function f1() { 12 alert(a); 13 } 14 function f2() { 15 alert(a); 16 } 17 function f3() { 18 alert(a); 19 } 20 })() 21 (function () { 22 var a = 456; 23 function f1() { 24 alert(a); 25 } 26 function f2() { 27 alert(a); 28 } 29 function f3() { 30 alert(a); 31 } 32 })() 33 </script> 34 </body> 35 </html>
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