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>