имитировать клик submit

<form method="post" class="ms2_form form-inline" role="form">
	<input type="hidden" name="key" value="{$product.key}"/>
	{if $product.options?}
            {$product.options | join : '; '}
        {/if}
	<div class="number">
		<div class="data-input">
			<input type="number" name="count" value="{$product.count}" size="5"/>
			<span class="plus">+</span>
			<span class="minus">-</span>
			<button class="btn btn-default" type="submit" name="ms2_action" value="cart/change">
</button>
	    </div>
	</div>
</form>

$('.number .minus').click(function () {
            var $input = $(this).parent().find('input[name="count"]');
            var count = parseInt($input.val()) - 1;
            count = count < 1 ? 0 : count;
            $input.val(count);
            $input.change();
            return false;
        });
        $('.number .plus').click(function () {
            var input = $(this).parent().find('input[name="count"]');
            input.val(parseInt(input.val()) + 1);
            input.change();
            alert(input.val);
            return false;
        });