js引出函数概念的案例
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <meta charset="utf-8">
5 <title></title>
6 <script>
7 /*输入两个数，再输入一个运算符，得到结果*/
8 var num1 = window.prompt("请输入第一个数");
9 num1=parseFloat(num1);
10 var num2 = window.prompt("请输入第二个数");
11 num2=parseFloat(num2);
12 var oper = window.prompt("请输入运算符");
13 var res = 0;
14 switch(oper)
15 {
16 case "+":
17 res = num1 + num2;
18 document.write(num1+oper+num2+"="+res);
19 break;
20 case "-":
21 res = num1 - num2;
22 document.write(num1+oper+num2+"="+res);
23 break;
24 case "*":
25 res = num1 * num2;
26 document.write(num1+oper+num2+"="+res);
27 break;
28 case "/":
29 res = num1 / num2;
30 document.write(num1+oper+num2+"="+res);
31 break;
32 defult:document.write("输入错误");
33 }
34 </script>
35 </head>
36 <body>
37 </body>
38 </html>
1 //jisuan.js
2 function p(){
3 /*输入两个数，再输入一个运算符，得到结果*/
4 var num1 = window.prompt("请输入第一个数");
5 num1=parseFloat(num1);
6 var num2 = window.prompt("请输入第二个数");
7 num2=parseFloat(num2);
8 var oper = window.prompt("请输入运算符");
9 var res = 0;
10 switch(oper)
11 {
12 case "+":
13 res = num1 + num2;
14 document.write(num1+oper+num2+"="+res);
15 break;
16 case "-":
17 res = num1 - num2;
18 document.write(num1+oper+num2+"="+res);
19 break;
20 case "*":
21 res = num1 * num2;
22 document.write(num1+oper+num2+"="+res);
23 break;
24 case "/":
25 res = num1 / num2;
26 document.write(num1+oper+num2+"="+res);
27 break;
28 defult:document.write("输入错误");
29 }
30
31
32 }
1 <!--putong.html-->
2
3 <!DOCTYPE html>
4 <html>
5 <head>
6 <meta charset="utf-8">
7 <title>调用函数实现计算功能</title>
8 <script src="jisuan.js" type="text/javascript"></script>
9 </head>
10 <body>
11 <input type="button" value="点我开始计算" onclick="p()">
12 </body>
13 </html>
运行效果如下图所示：