incrementare text velocemente

[br1]

esempio:

<SCRIPT LANGUAGE="JavaScript">
<!--
var fl=false;
var tm;
function sm() {
	document.frm.txt.value = parseInt(document.frm.txt.value,10) +1
	tm = setTimeout("sm()",(fl)?100:500);
}
//-->
</SCRIPT>

...

<form name=frm>
<input type=text name=txt value=0>
<input type=button value="+" onmousedown="sm();fl=true;" onmouseup="clearTimeout(tm);fl=false">
</form>

ciao