只能输入数字的文本框

思路：使用keyCode，阻止浏览器默认行为.

 1 <!DOCTYPE html>
 2 <html>
 3 <head lang="en">
 4     <meta charset="UTF-8">
 5     <title></title>
 6     <script>
 7         window.onload = function () {
 8             var oTxt = document.getElementById("txt1");
 9 
10             oTxt.onkeydown = function (event) {
11                 var bool1 = (event.keyCode!=8);  // backspace
12                 var bool2 = (event.keyCode!=37&&event.keyCode!=39);  // right, left
13                 var bool3 = (event.keyCode<48||event.keyCode>57);   // not number
14 
15                 if (bool1 && bool2 && bool3) {
16                     return false;
17                 }
18             }
19         }
20     </script>
21 </head>
22 <body>
23     <input type="text" id="txt1" />
24 </body>
25 </html>

View Code