只能在文本框内输入IP数字格式：_._._._
<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"><style>.a3{width:30;border:0;text-align:center}</style><script>function mask(obj){obj.value=obj.value.replace(/[^\d]/g,'')key1=event.keyCodeif (key1==37 || key1==39){ obj.blur();nextip=parseInt(obj.name.substr(2,1))nextip=key1==37?nextip-1:nextip+1;nextip=nextip>=5?1:nextipnextip=nextip<=0?4:nextipeval("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))+1nextip=nextip>=5?1:nextipnextip=nextip<=0?4:nextipeval("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 οnkeyup="mask(this)" onbeforepaste=mask_c()><input type=text name=ip2 maxlength=3 class=a3 οnkeyup="mask(this)" onbeforepaste=mask_c()><input type=text name=ip3 maxlength=3 class=a3 οnkeyup="mask(this)" onbeforepaste=mask_c()><input type=text name=ip4 maxlength=3 class=a3 οnkeyup="mask(this)" onbeforepaste=mask_c()></div></body></html>
