Remove all cart items from a button on a custom page using AJAX

Solution:

Use following code

add_action('wp_ajax_wc_woocommerce_clear_cart_url', 'wc_woocommerce_clear_cart_url');
add_action('wp_ajax_nopriv_wc_woocommerce_clear_cart_url', 'wc_woocommerce_clear_cart_url'); 
//added wc_ prefix in case of function name conflict

function wc_woocommerce_clear_cart_url() {
global $woocommerce;
$returned = ['status'=>'error','msg'=>'Your order could not be emptied'];
$woocommerce->cart->empty_cart();
if ( $woocommerce->cart->get_cart_contents_count() == 0 ) {    
    $returned = ['status'=>'success','msg'=>'Your order has been reset!'];       
}
die(json_encode($returned));
}

and the js/ajax side..:

$("#cancelorder").on('click',function(){        
    if(confirm('Are you sure you want to clear all rows?')){
        $.ajax({
        type: 'POST',
        dataType: 'json',
        url: '/wp-admin/admin-ajax.php?action=wc_woocommerce_clear_cart_url',
        data: {action : 'wc_woocommerce_clear_cart_url'},
        success: function (data) {
                if (data.status != 'success') {
                    alert(data.msg);
                } else {
                    $('#itemrows').html('');
                    addrows();
                }
            }   
        });
    } else {
        //back out with no action
    }
});