<form id="demo">
    <fieldset>
        <label for="demo_number">Number to format: <input type="text" id="demo_number"></label>
    </fieldset>
    <fieldset class="short">
        <label for="demo_thousandsSeparator">Thousands separator: <input type="text" id="demo_thousandsSeparator"></label>
        <label for="demo_decimalSeparator">Decimal separator: <input type="text" id="demo_decimalSeparator"></label>
        <label for="demo_decimalPlaces">Decimal places: <input type="text" id="demo_decimalPlaces"></label>
    </fieldset>
    <fieldset class="medium">
        <label for="demo_prefix">Prefix: <input type="text" id="demo_prefix"></label>
        <label for="demo_suffix">Suffix: <input type="text" id="demo_suffix"></label>
    </fieldset>
    <fieldset>
        <input type="button" id="demo_btn" value="Show formatted string">: <span id="demo_output">&nbsp;</span>
    </fieldset>
</form>

<script>
YUI().use("node", "datatype-number", "escape", function (Y) {

    function updateNumber (e) {
        e.preventDefault();
        var number = Y.Number.parse(Y.one("#demo_number").get("value")),
            output = Y.Number.format(number, {
                    prefix: Y.one("#demo_prefix").get("value"),
                    thousandsSeparator: Y.one("#demo_thousandsSeparator").get("value"),
                    decimalSeparator:Y.one("#demo_decimalSeparator").get("value"),
                    decimalPlaces: Y.Number.parse(Y.one("#demo_decimalPlaces").get("value")),
                    suffix: Y.one("#demo_suffix").get("value")
                });

        if(output === "") {
            output += "(Invalid number)"
        }

        Y.one("#demo_output").setHTML(Y.Escape.html(output));
    }

    Y.one("#demo_btn").on("click", updateNumber);
});
</script>
