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<!DOCTYPE html>
<html>
<head>
<title>JS tutorial</title>
<style type="text/css">
body {
    margin:10px 10px; padding:3px;
    background-color:#345; color:#aaa;
    font-family:"Arial", serif;
}
input {
    font-family:"Lucida", serif; font-size:1.2em; color:#555; text-align:center;
}
#res {
    padding:3px 4px; border:1px solid gray; color:#888; 
}
</style>
<script type="text/javascript">
    var pattern = /(a(b(cd)?)?)?/gi;
    var text = "abcdef";
    var match = pattern.exec(text);
    document.write(pattern + "<br />");
    document.write(text);
    function expressionTest() {
        if (pattern.test(text)) {       
            res.innerHTML = "";
            res.innerHTML = "- test:  'TRUE'<br />";    
            res.innerHTML += "- match.input:  '" + match.input + "'<br />";
            res.innerHTML += "- match[0]:  '" + match[0] + "'<br />";
            res.innerHTML += "- match[1]:  '" + match[1] + "'<br />";   
            res.innerHTML += "- match[2]:  '" + match[2] + "'<br />";   
            res.innerHTML += "- match[3]:  '" + match[3] + "'";         
        }
        else {
            res.innerHTML = "- test:  'FALSE'"; 
        }
        
    }
</script>
</head>
​
<body>
    <p id="res">results:</p>
    <form action="" method="post">
        <input type="button" onclick="expressionTest()" value="TEST EXPRESSION" />
    </form>
</body>
​
</html>