SOTD_006b

<!DOCTYPE html>
<html>
    <meta charset="UTF-8">
    <head>
        <script language = "javascript" type = "text/javascript">
            <!--


            function validateForm()
            {
                var tableNumber = Number(document.tableForm.table_number.value);
                var subtotal = Number(document.tableForm.subtotal.value);
                if(tableNumber == "" || tableNumber < 1 || tableNumber > 36)
                {
                    alert("Table number cannot be blank, and must be between 1 and 36, inclusive.");
                    document.tableForm.table_number.focus();
                }
                else if(subtotal == "" || subtotal <= 0)
                {
                    alert("Subtotal must be a non-negative integer greater than zero.  Please enter a valid value.");
                    document.tableForm.subtotal.focus();
                }
                else
                {
                    // The general means of rounding to a specified decimal place in javascript is as follows:

                    // a) multiply the number to be rounded by 10^x power,
                    //      where x is the decimal place to be rounded to.
                    // b) Apply Math.round() to the result.
                    // c) Divide the result of this by 10^x.
                    // (from www.javascriptkit.com/javatutors/round.shtml)
                    var tax = (Math.round(subtotal * 0.1 * 10**2))/10**2;
                    var total = subtotal + tax;
                    document.write("<b>Table number: </b>" + tableNumber + "<br />");
                    document.write("The subtotal was $" + subtotal.toFixed(2) + "<br />");
                    document.write("The tax was $" + tax + "<br />");
                    document.write("The total was $" + total.toFixed(2) + "<br />");
                }
            }
            //-->
        </script>
    </head>
    <body>
        <h1>Tables</h1>
        <hr />
        <form name="tableForm" class="inTable">
            Table number: <input type="text" name="table_number"><br />
            Subtotal: <input type="text" name="subtotal">
            <br />
            <input type="button" value="Submit" onclick="validateForm()">
        </form>
    </body>
</html>