add only specific product to cart

Question

So I need to include an add to cart button on a cms page so I'm trying to do this through a template block file in php. I can't figure out how to do this for just one static product though.

So the code for the usual add to cart button on product pages looks like this:

<?php $_product = $this->getProduct(); ?>
<?php $buttonTitle = $this->__('Add to Cart'); ?>
<?php if($_product->isSaleable()): ?>
    <div class="btn-add-box">
        <button type="button" title="<?php echo $buttonTitle ?>" class="btn btn-warning add-to-cart" style="margin-top:6px;width:200px;margin-left:20px;" data-url="<?php echo $this->getAddToCartUrl($_product, ['_secure' => true]) ?>" onclick="ga('ec:setAction', 'add'); ga('send', 'event', 'UX', 'click', 'add to cart');"><span><span><?php echo $buttonTitle ?></span></span></button>
        <?php echo $this->getChildHtml('', true, true) ?>
    </div>
<?php endif; ?>

But how do I do this for just the product with the ID 33? So I only want to display an add to cart button that adds the product with this ID on a static page. I've tried using a url on the cms page so like http://testing.co.uk/checkout/cart/add?product=[33]&qty=[1] but this goes to the cart, but doesn't add the product.

Answer 1

Try to use this:

<script type="text/javascript">
  function update_qty(id){
      var qty = document.getElementById('qty').value;
      document.getElementById('qty'+id).value = qty;
  }
</script>

<button type="submit"  onclick="update_qty(<?php echo $_product->getEntityId(); ?>);"
    title="<?php echo $block->escapeHtml(__('Add to Cart')); ?>"
    class="action tocart primary">
    <span><?php /* @escapeNotVerified */ echo __('Add to Cart') ?>
    </span>
</button>

for show this only for a specific product do something like this : if($_product->getId() == 'x') { show button }