<html>
<head>
<title>Matching a 16 digit credit card number
with variable number of space characters</title>
<script type="text/javascript" language="javascript">
<!-- //
function IsMatchingCard(str){
var myRegExp = /[0-9]{4} {0,1}[0-9]{4} {0,1}[0-9]{4} {0,1}[0-9]{4}/;
return myRegExp.test(str)
}
function TestGuess(){
alert(IsMatchingCard("1234 1234 1234 1234"));
}
// -->
</script>
</head>
<body>
<h3>This page allows you to enter and check a 16 digit credit card number</h3>
<form>
<button type="Button" onclick="TestGuess()">Click here to enter card
number</button>
</form>
</body>
</html>