[AkimovNY]

вот сделал, но как то немного тормозит, можно ли это оптимизировать?

$(window).resize(function() {
	    blockResize(".catalog_leader", ".catalog_item_card");
	})

function blockResize(blockName, itemName) {
	if ($(blockName).width() < 800) {					//3 товара
	    $(blockName + " " + itemName).css("width", "33.3%");
	    $(blockName + " " + itemName).slice(3,6).hide();
	}
	if ($(blockName).width() < 1000 && $(blockName).width() >= 800) {	//4 товаров
	    $(blockName + " " + itemName).css("width", "25%");
	    $(blockName + " " + itemName).slice(4,6).hide();
	    $(blockName + " " + itemName).slice(3,4).show();
	}
	if ($(blockName).width() < 1200 && $(blockName).width() >= 1000) {	//5 товаров
	    $(blockName + " " + itemName).css("width", "20%");
	    $(blockName + " " + itemName).slice(5,6).hide();
	    $(blockName + " " + itemName).slice(3,5).show();
	}
	if ($(blockName).width() >= 1200) {					//6 товаров
	    $(blockName + " " + itemName).css("width", "16.6%");
	    $(blockName + " " + itemName).slice(3,6).show();
	}
    }