C'è quello di windows.... ma solo x windows....

codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>
<head>
<title>Untitled</title>
</head>
<body>
<OBJECT ID=dlgHelper CLASSID="clsid:3050f819-98b5-11cf-bb82-00aa00bdce0b" WIDTH="0px" HEIGHT="0px"></OBJECT>


<script language="JavaScript" type="text/javascript">
<!--
function callColorDlg(aVar) {
	//display color dialog box
	sColor =  dlgHelper.ChooseColorDlg();
	//change decimal to hex
	sColor = sColor.toString(16);
	//add extra zeroes if hex number is less than 6 digits
  if (sColor.length < 6) {
  	var sTempString = "000000".substring(0,6-sColor.length);
  	sColor = sTempString.concat(sColor);
  }
	sInitColor = sColor;
	aVar.value = '#'+sColor;	
	return true;
} // function callColorDlg(aVar)
//-->
</script>

<input type="text" value="" id="colore">
<input type="button" value="clicca" onclick="callColorDlg(document.getElementById('colore'))">
</body>
</html>