简单计算器

 1 <!DOCTYPE html>
 2 <html>
 3 <head>
 4 <meta charset="UTF-8">
 5 <title>简单计算器</title>
 6 <script>
 7     function cal() {
 8         //获取文本框
 9         var input = document.getElementById("ss");
10         //获取框内的值
11         var ss = input.value;
12         try {
13             //计算
14             input.value = eval(ss);
15         } catch(e) {
16             input.value = "Error";
17         }
18     }
19 </script>
20 </head>
21 <body>
22     <input type="text" id="ss"/>
23     <input type="button" value="=" onclick="cal();"/>
24 </body>
25 </html>
mysql