// category page almost W3C valid

themes/default-bootstrap/product-compare.tpl

@@ -35,7 +35,7 @@
 //]]>
 </script>
 {/if}
-	<form method="post" action="{$link->getPageLink('products-comparison')|escape:'html'}" onsubmit="true" class="compare-form">
+	<form method="post" action="{$link->getPageLink('products-comparison')|escape:htmlall:'UTF-8'}" onsubmit="true" class="compare-form">
 		<div>
         <button type="submit" id="bt_compare{if isset($paginationId)}_{$paginationId}{/if}" class="btn btn-default button button-medium bt_compare"><span>{l s='Compare'} (<strong class="total-compare-val">{count($compared_products)}</strong>)<i class="icon-chevron-right right"></i></span></button>
          <input type="hidden" name="compare_product_count" class="compare_product_count" value="{count($compared_products)}" />