Javascript条件语句之if else
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8">
5 <title>hello world</title>
6 </head>
7 <body>
8 <p>如果时间小于10：00，则生成问候“good morning，如果时间大于10：00小于20：00，则生成问候“good day”，否则生成问候“goodevening”</p>
9 <button onclick="myFunction()">点击这里</button>
10 <p id="demo"></p>
11 <script>
12 function myFunction(){
13 var x='';
14 var time= new Date().getHours();
15 if (time<10){
16 x ="good morning!"
17 }
18 else if(10<time<20){
19 x ="good day"
20
21 }
22 else{
23 x ="good evening"
24 }
25 document.getElementById("demo").innerHTML=x
26 }
27
28 </script>
29 </body>
30 </html>
Javascript之switch
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8">
5 <title>JavaScript Switch</title>
6 </head>
7 <body>
8 <p>click this button to get witch day today</p>
9 <button onclick="myFunction()">click it</button>
10 <p id="demo"></p>
11 <script>
12 function myFunction(){
13 var x;
14 var d = new Date().getDay();
15 console.log(d)
16 switch (d){
17 case 0:x="今天是星期日";
18 break;
19 case 1:x="今天是星期一";
20 break;
21 case 2:x="今天是星期二";
22 break;
23 case 3:x="今天是星期三";
24 break;
25 case 4:x="今天是星期四";
26 break;
27 case 5:x="今天是星期五";
28 break;
29 case 6:x="今天是星期六";
30 break;
31 }
32 document.getElementById("demo").innerHTML=x
33 }
34
35 </script>
36 </body>
37 </html>
Javascript之for循环
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8">
5 <title>JavaScript for 循环</title>
6 </head>
7 <body>
8 <p>cars is </p>
9 <script>
10 var cars = ["bms","volovo","byd","benz", "..."]
11 for (var i=0; i<cars.length; i++){
12 document.write(cars[i], +'<br>')
13 console.log(cars[i])
14 }
15 </script>
16 </body>
17 </html>
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8">
5 <title>JavaScript for 循环啊</title>
6 </head>
7 <body>
8 <button onclick="myFunction()">click here to calculate it </button>
9 <p id="demo"></p>
10 <script>
11 function myFunction(){
12 var x ="";
13 for (var i=0; i<5; i++){
14 x = x + "number is "+ i + "<br>"
15
16 }
17 document.getElementById("demo").innerHTML=x
18 }
19
20 </script>
21 </body>
22 </html>
Javascript之for...in循环
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="uff-8">
5 <title>JavaScript for/in 循环</title>
6 </head>
7 <body>
8 <script>
9 var person={
10 fname:"Bill",
11 lname:"Gates",
12 age:56,
13 hobby:"sport"
14 }
15 for (x in person){
16 txt = person[x]
17 console.log(txt)
18 }
19
20 </script>
21 </body>
22 </html>
Javascript之while循环
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8">
5 <title>JavaScript while 循环啊</title>
6 </head>
7 <body>
8 <p>JavaScript while 循环啊</p>
9 <p>
10 while (条件){
11 需要执行的代码块
12 }
13 </p>
14 <p>当i<10，打印所有值</p>
15 <button onclick="myFunction()">click here</button>
16 <p id="demo"></p>
17 <script>
18 function myFunction(){
19 var x='', i=0;
20 while (i<10){
21 x = x +"this number is " + i + "<br>";
22 i++
23 }
24 document.getElementById("demo").innerHTML=x
25 }
26 </script>
27
28 </body>
29 </html>
JavaScript之do...while循环
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8">
5 <title>JavaScript do while</title>
6 </head>
7 <body>
8 <p>
9 语法:do/while 循环是 while 循环的变体。该循环会在检查条件是否为真之前执行一次代码块，然后如果条件为真的话，就会重复这个循环。
10 do {
11 需要执行的代码块
12 }
13 while(条件);
14 </p>
15 <p>点击下面按钮，只要i小于5就一直循环代码</p>
16 <button onclick="myFunction()">点击这里</button>
17 <p id="demo"></p>
18 <script>
19 function myFunction(){
20 var x="", i=0
21 do {
22 x = x + "该数字为"+ i +"<br>";
23 i++
24 }
25 while (i<5)
26 document.getElementById("demo").innerHTML=x
27 }
28 </script>
29 </body>
30 </html>
JavaScript之for循环遍历数组
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8">
5 <title>JavaScript for 循环遍历数组值</title>
6 </head>
7 <body>
8 <p>for 循环打印数组所有值啊</p>
9 <button onclick="myFunction()">点击这里打印所有值</button>
10 <p id="demo"></p>
11 <script>
12 function myFunction(){
13 //定义一个数组
14 cars=["BMW","Volvo","Saab","Ford"];
15 //定义一个自增变量i=0
16 var i=0
17 for (;cars[i];){
18 document.write(cars[i]+"<br>");
19 i++
20 }
21 }
22 </script>
23 </body>
24 </html>
JavaScript条件语句之while循环遍历数组
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8">
5 <title>JavaScript while 循环遍历数组值</title>
6 </head>
7 <body>
8 <p>while 循环遍历数组值啊</p>
9 <button onclick="myFunction()">点击这里遍历所有值</button>
10 <p id="demo"></p>
11 <script>
12 function myFunction(){
13 //定义两个变量
14 var cars=["BMW","Volvo","Saab","Ford"];
15 i=0;
16 while (cars[i]){
17 document.write(cars[i]+"<br>");
18 i++
19 }
20
21 }
22 </script>
23 </body>
24 </html>
标签：语句,10,JavaScript,11,Javascript,while,循环,条件,var From： https://www.cnblogs.com/wenzm/p/17022391.html