JS生成Guid

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <title></title>
    <script type="text/javascript">
        var getGuid = function () {
            var guid = "";
            for (var i = 1; i <= 32; i++) {
                var n = Math.floor(Math.random() * 16.0).toString(16);
                guid += n;
                if ((i == 8) || (i == 12) || (i == 16) || (i == 20))
                    guid += "-";
            }
            return guid;
        }
    </script>
</head>
<body>
<input type="button" value="测试" onclick="alert(getGuid());"/>
</body>
</html>
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