I’m trying to calculate a value by subtracting the magento subtotal of my cart from another value, let’s say 50. This is the code:

<script type="text/javascript">
function minus_number() {
        var a  = document.querySelector("#spend");
        var first_number = '50.00';
        var second_number = '<?php echo Mage::getSingleton('checkout/cart')->getQuote()->getGrandTotal(); ?>';
        var result = parseInt(first_number).toFixed(2) - parseInt(second_number).toFixed(2);
        a.innerHTML = result.toFixed(2);

Now it kind of works, but the result isn’t right. I think the issue is that the magento subtotal doesn’t include decimals? So if let’s say the subtotal is 6.98 the result is 44.00 so I assume it only subtracts the 6?


Try with parseFloat() instead of parseInt(). Everything else should be working ok.

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