只能是一些限定的东西
ENTER键可以让光标移到下一个输入框
<input onkeydown="if(event.keyCode==13)event.keyCode=9" > <br>
只能是中文<input onkeyup="value=value.replace(/[ -~]/g,'')" onkeydown="if(event.keyCode==13)event.keyCode=9"> <br>
屏蔽输入法<input style="ime-mode:disabled" onkeydown="if(event.keyCode==13)event.keyCode=9"> <br>
只能输入英文和数字<input onkeyup="value=value.replace(/[\W]/g,'') "onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))" onkeydown="if(event.keyCode==13)event.keyCode=9"> <br>
只能是数字<input onkeyup="value=value.replace(/[^\d]/g,'') "onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))"><br>
只能显示，不能修改<input readonly value="只能显示，不能修改">
只能是数字，判断按键的值。
<script language=javascript>
function onlyNum()
{
if(!((event.keyCode>=48&&event.keyCode<=57)||(event.keyCode>=96&&event.keyCode<=105)||(event.keyCode==8)))
event.returnValue=false;
}
</script>
<input onkeydown="onlyNum();">
附：获取键盘的KeyCode
<html>
<head>
<script language="javascript">
ns4 = (document.layers) ? true : false;
ie4 = (document.all) ? true : false;
function keyDown(e){
if(ns4){
var nkey=e.which;
var iekey='现在是ns浏览器';
var realkey=String.fromCharCode(e.which);
}
if(ie4){
var iekey=event.keyCode;
var nkey='现在是ie浏览器';
var realkey=String.fromCharCode(event.keyCode);
if(event.keyCode==32){realkey='\' 空格\''}
if(event.keyCode==13){realkey='\' 回车\''}
if(event.keyCode==27){realkey='\' Esc\''}
if(event.keyCode==16){realkey='\' Shift\''}
if(event.keyCode==17){realkey='\' Ctrl\''}
if(event.keyCode==18){realkey='\' Alt\''}
}
alert('ns浏览器中键值:'+nkey+'\n'+'ie浏览器中键值:'+iekey+'\n'+'实际键为'+realkey);
}
document.onkeydown = keyDown;
if(ns4){
document.captureEvents(Event.KEYDOWN);}
</script>
</head>
<body>
//Javascript Document.
<hr>
<center>
<h3>请按任意一个键。。。。</h3>
</center>
</body>
</html>
限制网页用键盘
<body onkeydown="alert('禁用');return false;">
限制键盘的某个键：body onkeydown="if(event.keyCode==num){alert('禁用');return false;}
再加个找按键的值
<script>
function show(){
alert("ASCII代码是："+event.keyCode);
}
</script>
<body onkeydown="show()">
只能是IP地址
<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.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>
用#default#savehistory防止后退清空text文本框：
<HTML>
<HEAD>
<META NAME="save" CONTENT="history">
<STYLE>
.saveHistory {behavior:url(#default#savehistory);}
</STYLE>
</HEAD>
<BODY>
<INPUT class=saveHistory type=text id=oPersistInput>
<input type=button onclick='javascript:location.href="http://www.webjx.com/"' value='点击进入,再按后退键试试？'>
</BODY>
</HTML>
TEXTAREA自适应文字行数的多少
<textarea rows=1 name=s1 cols=27 onpropertychange="this.style.posHeight=this.scrollHeight">
上传预览图片
<img id=pic src=http://webdesign.chinaitlab.com/UploadFiles_8014/200604/20060418102923102.gif>
<input type=file name=file><input type=button onclick=pic.src=file.value value=预览图片>
<input type=button onclick=alert(file.value) value=图片地址>
<input type=button onclick="file.outerHTML=file.outerHTML.replace(/value=\w/g,'')" value="清除file里字">
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