Declare javascript variable in observer method [duplicate]

Question

I got some great advice on how to create a module to specify the price of a product when it is added to cart here: Dynamically calculated prices save before add to cart

I have a custom script within configurable.phtml that determines the price of an item depending on the configurable attributes (and other details). I need to pass this price string into the module's method within the Observer.php. How would I do this?

The /app/code/local/{namespace}/{yourmodule}/etc/config.xml:

<config>
    ...
    <frontend>
        ...
        <events>
            <checkout_cart_product_add_after>
                <observers>
                    <unique_event_name>
                        <class>{{modulename}}/observer</class>
                        <method>modifyPrice</method>
                    </unique_event_name>
                </observers>
            </checkout_cart_product_add_after>
        </events>
        ...
    </frontend>
    ...
</config>

The Observer class at /app/code/local/{namespace}/{yourmodule}/Model/Observer.php (see comment next to $price declaration):

 class <namespace>_<modulename>_Model_Observer
{
    public function modifyPrice(Varien_Event_Observer $obs)
    {
        // Get the quote item
        $item = $obs->getQuoteItem();
        // Ensure we have the parent item, if it has one
        $item = ( $item->getParentItem() ? $item->getParentItem() : $item );
        // Load the custom price
        $price = "your custom price logic"; //I need the value generated in the javascript here
        // Set the custom price
        $item->setCustomPrice($price);
        $item->setOriginalCustomPrice($price);
        // Enable super mode on the product.
        $item->getProduct()->setIsSuperMode(true);
    }



}

The javascript function that declares price (I need this in module observer):

function selectAndAddToCart(value)
{
    var product_id= <?=$product_id ?>;
    var colorSelected = $j("#attribute92 option:selected").val();

    $j('#attribute136 option[value="' + value + '"]').prop('selected',true);

    $j('#attribute136').removeClass('validation-failed').addClass('validation-passed');

    var price = newPriceArray[value][colorSelected]; //the value I need to pass to module
    console.log('The newPriceArray in selectAndAddToCart ' + price); //this is logging correctly


}