<body>
<script language=Javascript>
function objFocus(n) //控制光标选中光标后一字符
{
if (arguments.length == 0) var n=0;
var e = window.event.srcElement;
var r = e.createTextRange();
r.moveStart('character', n);
r.collapse(true);
r.select();
var s = document.selection.createRange().duplicate().duplicate();
s.moveStart('character', 1);
s.setEndPoint("EndToEnd", r);
s.select();
}
function keyPress(e) //内容填空
{
var k = String.fromCharCode(window.event.keyCode);
if(!/^\d/.test(k)) return false; //不准输入非法字符
e.focus();
var range = e.createTextRange();
var select1 = document.selection.createRange().duplicate();
select1.setEndPoint("StartToStart",range);
var s1 = select1.text; //得到光标左边的字串
var s2 = e.value.substr(s1.length); //得到光标右边的字串
e.value = s1.substring(0, s1.length-1) + k + s2; //给文本框赋值
var n = s1.length;
if (n==4 || n==7 || n==10 || n==13) n++;
objFocus(n);
window.event.keyCode = 0;
event.returnValue = false;
}
function keyDown(e) //删除回退按方向键时的处理
{
var k = window.event.keyCode;
if (!(k>=48 && k<=57 //数字0-9
|| k==46 //删除键 Del
|| k==8 //回删链 Backspace
|| k==37 //方向链 ←
|| k==39 //方向键 →
|| k==9 //制表键 Tab
|| k==13 //回车键 Enter
)) return false; //屏蔽非上面所列的键
e.focus();
var range = e.createTextRange();
var select1 = document.selection.createRange().duplicate();
select1.setEndPoint("StartToStart",range);
var s1 = select1.text; //得到光标左边的字串
var s2 = e.value.substr(s1.length); //得到光标右边的字串
var n = s1.length;