<html>
<head>
<script language="javascript">
function checkdata()
{
if(window.event.keyCode<48 || window.event.keyCode>57)
{
event.keyCode=0;
event.returnValue=false;
}
}
</script>
</head>
<body>
<form name=form1
<input type='text' name=aa onkeydown="checkdata()">
</form>
</body>
</html>
<head>
<script language="javascript">
function checkdata()
{
if(window.event.keyCode<48 || window.event.keyCode>57)
{
event.keyCode=0;
event.returnValue=false;
}
}
</script>
</head>
<body>
<form name=form1
<input type='text' name=aa onkeydown="checkdata()">
</form>
</body>
</html>
<input type = text name = t1 onchange=change(this)>function change(id)
{
dights="0123456789";
for (i=0;i<id.value.length;i++)
{
if (dights.indexOf(id.value.substr(i,1))==-1)
{
alert("你输入的不正确,请不要输入非法字符!!");
id.value="";
id.focus();
return false;
}
}
}
<html>
<head>
<script language="javascript">
function checkdata()
{
if(isNaN(form1.aa.value))
{
alert('只能输入数字!');
form1.aa.value=form1.aa.value.substring(0,form1.aa.value.length-1);
form1.aa.focus();
return false;
}
}
</script>
</head>
<body>
<form name=form1>
<input type='text' name=aa onpropertychange="checkdata()">
</form>
</body>
</html>
<html>
<head>
<title>输入屏蔽 </title>
<style>
.font{font-size:40;font-family:方正中楷繁体;color:#de3076}
.textarea1{background='#bde6fd';color='#FF66CC';border='0'}
.input1{}
.input2{}
</style>
</head>
<BODY >
<center>
<font size="15" face="文鼎彩云繁" color="red">对输入字符的屏蔽</center>
<form onSubmit="return false;">
<font class="font"> 1.这个文本框内不能输入特殊字符,如!@#$%^&*等:</font><br>
<textarea class="textarea1" rows="2" cols="80" name="comments" onKeypress="if ((event.keyCode > 32 && event.keyCode < 48) || (event.keyCode > 57 && event.keyCode < 65) || (event.keyCode > 90 && event.keyCode < 97)) event.returnValue = false;"></textarea>
<br>
<br>
<font class="font"> 2.这个文本框不能输入单引号或双引号:</font><br>
<input class="textarea1" size="80" type="text" name="txtEmail" onKeypress="if (event.keyCode==34 || event.keyCode==39) event.returnValue = false;">
<br>
<br>
<font class="font"> 3.这个文本框只能输入数字:</font><br>
<input class="textarea1" size="80" type="text" name="txtPostalCode" onKeypress="if (event.keyCode < 45 || event.keyCode > 57) event.returnValue = false;">
</form>
</BODY>
</html>