如何在表单中限制输入的字符？急用~~~~~~~~~~~~~~~~~~~~~~~~

给你几个例子,希望有帮助:::::::1......
<html>
<head>
<title></title>
</head>
<body>
<form name="form1">
<input type="text" name="n" maxlength="4">年
<input type="text" name="y" maxlength="2">月
<input type="text" name="r" maxlength="2">日
<input type="text" name="rksl" maxlength="6">入库数量
</form>
</body><script language="JavaScript">
if (document.layers)
document.captureEvents(event.KeyPress);
function blockA(e)
{
  if (document.layers)
        var keyChar =e.which;
  if (document.all)
        var keyChar =event.keyCode;
  if (keyChar>57 || keyChar<48)
    {
        alert('请输入数字！');
        return false;
    }
}
document.form1.n.onkeypress = blockA;
document.form1.y.onkeypress = blockA;
document.form1.r.onkeypress = blockA;
function blockB(t)
{
  if (document.layers)
        var keyChar =e.which;
  if (document.all)
        var keyChar =event.keyCode;
  if (keyChar>57  || keyChar<46 || (keyChar>46 && keyChar<49))               //查ASCII码的值,限制keyChar的范围,这样可以控制键盘输入
    {
        alert('请输入数字！');
        return false;
    }
}
document.form1.rksl.onkeypress=blockB;
</script></html>
2.....<html>
<head>
<title></title>
</head>
<body>
<form name="form1">
<input type="text" name="n" maxlength="4">年
<input type="text" name="y" maxlength="2">月
<input type="text" name="r" maxlength="2">日
<input type="text" name="rksl" maxlength="6">入库数量
</form>
</body><script language="JavaScript">
if (document.layers)
document.captureEvents(event.KeyPress);
function blockA(e)
{
  if (document.layers)
        var keyChar =e.which;
  if (document.all)
        var keyChar =event.keyCode;
  if (keyChar>57 || keyChar<48)
    {
        alert('请输入数字！');
        return false;
    }
}
document.form1.n.onkeypress = blockA;
document.form1.y.onkeypress = blockA;
document.form1.r.onkeypress = blockA;
function blockB(t)
{
  if (document.layers)
        var keyChar =e.which;
  if (document.all)
        var keyChar =event.keyCode;
  if (keyChar>57  || keyChar<46 || (keyChar>46 && keyChar<49))               //查ASCII码的值,限制keyChar的范围,这样可以控制键盘输入
    {
        alert('请输入数字！');
        return false;
    }
}
document.form1.rksl.onkeypress=blockB;
</script></html>

解决方案 »

免费领取超大流量手机卡，每月29元包185G流量+100分钟通话, 中国电信官方发货

<html>
<head>
<title>入库记录查询 </title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<link href="CssLib/TOOLBARS.CSS" rel="stylesheet" type="text/css">
<script language="javascript">

</script>
</head><body bgcolor="#deebff" leftmargin="0" topmargin="0" marginwidth="0" marginheight="0">
<br>
<table width="80%" border="0" align="center" cellpadding="2" cellspacing="0">
  <tr>
    <td> <div align="center"><strong>入库记录查询 </strong> </div>
      <div align="center"></div></td>
  </tr>
</table>
<form name="form1">
  <div align="center">
    <table width="51%" height="203" border="1" cellpadding="2" cellspacing="0">
      <tr>
        <td><div align="center">
            <select name="bh" >
              <option value="1">物资名称</option>
              <option value="2">规格型号</option>
            </select>
          </div></td>
        <td><div align="center">
            <input type="text" name="textfield">
          </div></td>
      </tr>
      <tr>
        <td><div align="center">入库人：</div></td>
        <td><div align="center">
            <input type="text" name="psnname">
          </div></td>
      </tr>
      <tr>
        <td><div align="center">入库日期：</div></td>
        <td><div align="center">从
            <input name="s_year" type="text" size="4" maxlength="4">
            年
            <input name="s_month" type="text" size="2" maxlength="2">
            月
            <input name="s_day" type="text" size="2" maxlength="2">
            日 </div></td>
        <td><div align="center">到
            <input name="e_year" type="text" size="4" maxlength="4">
            年
            <input name="e_month" type="text" size="2" maxlength="2">
            月
            <input name="e_day" type="text" size="2" maxlength="2">
            日 </div></td>
      </tr>
    </table>
    <br>
    <table width="148" height="42" border="0" cellpadding="2" cellspacing="0">
      <tr>
        <td><div align="center">
            <input type="button" name="button1" value="查询" onclick="validate()">
          </div></td>
        <td><div align="center">
            <input type="reset" name="cancel" value="取消">
          </div></td>
      </tr>
    </table>
  </div>
</form><script language="JavaScript">

</script></body>
</html>
<HTML>
<HEAD>
<META NAME="GENERATOR" Content="Microsoft Visual Studio 6.0">
<TITLE></TITLE>
<script>
function foo(){
number.onblur = function (){
var nValue = parseInt(number.value);
if(isNaN(nValue))
alert("请输入数字");
else if(nValue < 0 || nValue > 1000)
alert("数字必须是0到1000之间的数");
}
}
</script>
</HEAD>
<BODY>
输入一个0到1000的数：
<input type="text" name="number" onfocus="foo()">
</BODY>
</HTML>
<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<title>只输入数字的几种方法</title>
<style>
td{font-size:12px}
</style>
</head><body><table border="1" width="90%" bordercolor="#000000" cellspacing="0" cellpadding="0" bordercolorlight="#000000" bordercolordark="#FFFFFF">
  <tr>
    <td width="100%"><input onkeyup="this.value=this.value.replace(/\D/g,'')"
      onafterpaste="this.value=this.value.replace(/\D/g,'')">
     <br>
     try:<input onkeyup="this.value=this.value.replace(/\D/g,'')" onafterpaste="this.value=this.value.replace(/\D/g,'')"></td>
  </tr>
  <tr>
    <td width="100%"><input name=txt1 onchange="if(/\D/.test(this.value)){alert('只能输入数字');this.value='';}"><br>
    try:<input name=txt1 onchange="if(/\D/.test(this.value)){alert('只能输入数字');this.value='';}"></td>
  </tr>
  <tr>
    <td width="100%"><input onkeyup="if(isNaN(value))execCommand('undo')" onafterpaste="if(isNaN(value))execCommand('undo')"><br>
    try:<input onkeyup="if(isNaN(value))execCommand('undo')" onafterpaste="if(isNaN(value))execCommand('undo')"></td>
  </tr>
  <tr>
    <td width="100%" align="right"><a href="http://fason.nease.net">【阿信的小天地】</a></td>
  </tr></table></body></html>
<html><head>
<meta http-equiv="Content-Language" content="zh-cn">
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<title>表单验证总汇（一）</title>
<style>
body{font-size:12px}
</style>
</head><body>
<script language=javascript>
function onlyEng()
{
  if(!(event.keyCode>=65&&event.keyCode<=90))
    event.returnValue=false;
}
function onlyNum()
{
  if(!((event.keyCode>=48&&event.keyCode<=57)||(event.keyCode>=96&&event.keyCode<=105)))
//考虑小键盘上的数字键
    event.returnValue=false;
}
function isEmail(strEmail) {
if (strEmail.search(/^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/) != -1)
  return true;
else
  alert("oh");
}
</script>
<div align="center">
  <center>
<table border="1" width="90%" cellspacing="0" cellpadding="0" style="font-size:12px" bordercolor="#000000" bordercolorlight="#000000" bordercolordark="#FFFFFF">
  <tr>
    <td width="100%">只能是汉字:<input onkeyup="value=value.replace(/[^\u4E00-\u9FA5]/g,'')"></td>
  </tr>
  <tr>
    <td width="100%">只能是英语字符:<input onkeydown="onlyEng();"></td>
  </tr>
  <tr>
    <td width="100%">只能是数字:<input onkeydown="onlyNum();"></td>
  </tr>
  <tr>
    <td width="100%">只能是英文字母和数字:<input onkeyup="value=value.replace(/[\W]/g,'') " onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))"></td>
  </tr>
  <tr>
    <td width="100%">验证email格式:<input type=text onblur=isEmail(this.value)></td>
  </tr>
  <tr>
    <td width="100%">不能输入汉字<INPUT onpaste="return false;" style="IME-MODE: disabled; WIDTH: 400px" value="I only accept English input! Thanks for corporation!" name=textfield> </td>
  </tr>
  <tr>
    <td width="100%" align="right"><a href="http://fason.nease.net">【阿信的小天地】</a></td>
  </tr>
</table>  </center>
</div></body></html>