Change Woocommerce product quantity on a link click with jQuery
In Wordpress you need to replace the $ alias by jQuery. Use instead the following:
<a id="quantity150" class="button" href="#">150</a><script>jQuery( function($) { $('#quantity150').click( function(e) { e.preventDefault(); $('[name="quantity"]').val('150'); console.log('#quantity150 was clicked'); });});</script>Tested an works on WooCommerce single product pages.