on

English [?n] US [ɑ:n]

prep.(??? ???) to;(??? ???) on...; ..

adv.(??, ????, ????) ??, (??) ???

adj.?? ? ??; ki]

n.Key; ?, ??, ??; (???) keyvt.?? ??...; key? ?????

adj. ???(???, ?????) ???(?? ?? ??? ??? ???) ???(?? ???) ???(??? ???); ; (??? ???)

??; ??? ?? ??? ??? ??; (...) ???? ???

n.

vt. ????(?? ? ??? ?? ???), ?????(? ??? ?) ????; down

3?? ??: downs ??: downs ?? ??: downing ?? ??: downed ?? ??: downed

?????? onkeydown ?? ???

??: ???? ??? ?? ?? ? ?????.

??: ??onkeydown="SomeJavaScriptCode"

????: SomeJavaScriptCode ?????. ? ???? ??? ? ??? JavaScript? ?????.?

?????? onkeydown ?? ?

<html>
<body>
<script type="text/javascript">
function noNumbers(e)
{
var keynum
var keychar
var numcheck

if(window.event) // IE
	{
	keynum = e.keyCode
	}
else if(e.which) // Netscape/Firefox/Opera
	{
	keynum = e.which
	}
keychar = String.fromCharCode(keynum)
numcheck = /\d/
return !numcheck.test(keychar)
}
</script>

<form>
數(shù)字無法輸入（小鍵盤上的數(shù)字可以）:
<input type="text" onkeydown="return noNumbers(event)" />
</form>

</html>

???? ?? ?

??? ????? ??? "???? ??" ??? ?????