Update price automatically when quantity changed on product page Magento

Question

I am looking to have the product price automatically updated based on the quantity the customer has chosen.

Currently when you choose a custom option in magento the

Answer 1

Using jquery you can do this

$('#qty').keyup(function(){
    if($(this).val() != '' && isNumber($(this).val()) && $(this).val() > 0)
    {
       var price = $('#real_price').val() * 1;
       var qty = $(this).val() * 1;
       var total = price * qty;
       $('#price').html(total);
    }
    else
    {
       $('#price').html('500');    
    }
});

function isNumber(n) {
    return !isNaN(parseFloat(n)) && isFinite(n);
}

FIDDLE