<input type="text" value = "" onChange="this.value=checkOnchg(this.value);" ><script type="text/javascript">
/*
function checkvalue(str){
if(event.keyCode<48 || event.keyCode>57) {
str=str.toUpperCase().replace(String.fromCharCode(event.keyCode),"");
}
return str;
}
*/function checkOnchg(str){
var checkstr = "1234567890";
var strRtn = str;
for(i=0;i<str.length;i++){
if(checkstr.indexOf(str.charAt(i)) == -1){
strRtn=strRtn.replace(str.charAt(i),"");
}
}
return strRtn;
}</script>
/*
function checkvalue(str){
if(event.keyCode<48 || event.keyCode>57) {
str=str.toUpperCase().replace(String.fromCharCode(event.keyCode),"");
}
return str;
}
*/function checkOnchg(str){
var checkstr = "1234567890";
var strRtn = str;
for(i=0;i<str.length;i++){
if(checkstr.indexOf(str.charAt(i)) == -1){
strRtn=strRtn.replace(str.charAt(i),"");
}
}
return strRtn;
}</script>
function getSel()
{
var n=t.value;
if(isNaN(parseInt(n)))
alert('不是一个书');
}
</script><input type="text" name="t">
</textarea><br>
<input type="button" value="点" onmousedown="getSel()">
function f(obj){
if(!event.shiftKey)
if(event.keyCode>=48&&event.keyCode<=57||event.keyCode>=96&&event.keyCode<=105||event.keyCode==110||event.keyCode==190)
return true
return false
}
</script>
<body>
<input onkeydown="return f(this)" />
</body>