Javascript Count Quantities

[Nathan]

<form action="/proc" method="post" onsubmit="return check();">
                <input type="hidden" name="twelve" value="399">
                <div class="quantity">
                    <input type='button' value='-' class='qtyminus' field='quantity12' />
                    <input type='text' id='quantity12' value='0' class='qty' name="quantity12"/>
                    <input type='button' value='+' class='qtyplus' field='quantity12' />
                </div>

</div>
            <div style="width:300px;float:left;margin-left:30px;">
                    <input type="hidden" name="twentyfour" value="547">
                        <div class="quantity">
                            <input type='button' value='-' class='qtyminus' field='quantity11' />
                            <input type='text' id='quantity11' value='0' class='qty' name="quantity11"/>
                            <input type='button' value='+' class='qtyplus' field='quantity11' />
                        </div>
                </div>
            <div id="clearfix"></div>
                        <div style="margin-top:175px;"><input type="submit"/></div>
            </form> 

Javascript:

<script type="text/javascript">
        function check() {
            var elements = document.getElementsByName("quantity11");
            var elements1 = document.getElementsByName("quantity12");
            for (var i=0; i<elements.length; i++) {
                    var nmbr = parseInt(elements[i].value,10);
                    var nmbr1 = parseInt(elements1[i].value,10);
                    if ((nmbr*2) + nmbr1 > <?php echo $maxqtyorder; ?>){
                        alert("You've selected more treats than your package allows.");
                        return false;
                    }
                }
            return true;
        }
    </script> 

I have a page that includes 2 different options to select. You can select the quantity before you add to your cart.  I'm trying to make sure that the quantity the customer selects is not more than a certain total I've already passed to that page.  After about an hour of trial and error it worked!

 

HTML: