只能输入数字：<form>
<input type="text" name="money" onkeypress="checkNum(this)">
</form>
<script language="javascript" type="text/javascript">
function checkNum()
{
if(window.event.keyCode > '9'.charCodeAt(0) ||
window.event.keyCode < '0'.charCodeAt(0))
{
window.event.returnValue=false;
}
}
</script>
<input type="text" name="money" onkeypress="checkNum(this)">
</form>
<script language="javascript" type="text/javascript">
function checkNum()
{
if(window.event.keyCode > '9'.charCodeAt(0) ||
window.event.keyCode < '0'.charCodeAt(0))
{
window.event.returnValue=false;
}
}
</script>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<meta name="GENERATOR" content="Microsoft FrontPage 6.0">
<meta name="ProgId" content="FrontPage.Editor.Document">
<style>
.a3{width:30;border:0;text-align:center}
</style>
<script>
function mask(obj){
obj.value=obj.value.replace(/[^\d]/g,'')
key1=event.keyCode
if (key1==37 || key1==39)
{ obj.blur();
nextip=parseInt(obj.name.substr(2,1))
nextip=key1==37?nextip-1:nextip+1;
nextip=nextip>=5?1:nextip
nextip=nextip<=0?4:nextip
eval("ip"+nextip+".focus()")
}
if(obj.value.length>=3)
if(parseInt(obj.value)>=256 || parseInt(obj.value)<=0)
{
alert(parseInt(obj.value)+"IP地址错误！")
obj.value=""
obj.focus()
return false;
}
else
{ obj.blur();
nextip=parseInt(obj.name.substr(2,1))+1
nextip=nextip>=5?1:nextip
nextip=nextip<=0?4:nextip
eval("ip"+nextip+".focus()")
}
}
function mask_c(obj)
{
clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))
}</script>
<title>IP地址输入</title></head>
<body>IP地址输入
<div style="border-width:1;border-color:balck;border-style:solid;width:165;font-size:9pt">
<input type=text name=ip1 maxlength=3 class=a3 onkeyup="mask(this)" onbeforepaste=mask_c()>.
<input type=text name=ip2 maxlength=3 class=a3 onkeyup="mask(this)" onbeforepaste=mask_c()>.
<input type=text name=ip3 maxlength=3 class=a3 onkeyup="mask(this)" onbeforepaste=mask_c()>.
<input type=text name=ip4 maxlength=3 class=a3 onkeyup="mask(this)" onbeforepaste=mask_c()>
</div>
</body></html>
if(/^-?\d+(\.\d*)$/.test(str))
{
//数字
}if(/^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/.test(str) && parseInt(RegExp.$1)<256 && parseInt(RegExp.$2)<256 && parseInt(RegExp.$3)<256 && parseInt(RegExp.$4)<256)
{
//IP
}