<input type=text onchange="checkit(this)">
<script>
function checkit(e){
if(!/^\d+(\.\d{1,6})?$/.test(e.value))
alert("not ok");
}
</script>
<script>
function checkit(e){
if(!/^\d+(\.\d{1,6})?$/.test(e.value))
alert("not ok");
}
</script>
<head><title>dd</title>
<script language="javascript">
function checkit(e){
if(!/^\d+(\.\d{1,6})?$/.test(e.value))
alert("not ok");
}
</script>
</head>
<body>
<form>
Input data:<input type="text" size=10 onchange="checkit(this)"></form>
</body>
</html>