Change && to &&
add_filter('woocommerce_add_to_cart_redirect', 'malpani_redirect_checkout_add_cart'); function malpani_redirect_checkout_add_cart() { if (isset($_POST["buynow"]) && $_POST["buynow"] === "2") { return wc_get_checkout_url(); } } add_filter('woocommerce_after_add_to_cart_button', 'malpani_add_buy_button'); function malpani_add_buy_button() { echo '<input id="buynowinput" name="buynow" value="1" hidden> <button type="button" id="buy_now" class="buy_now button">Buy Now</button> <script> jQuery(document).ready(function ($) { $("#buy_now").click(function (e) { $("#buynowinput").val(2); $(".single_add_to_cart_button").click(); e.stopPropagation(); e.preventDefault(); }) }); </script>';