Meaning of this two jquery expression?

HTML CODE

<tr class="roti">

    <td class="ts" rowspan="2">
        <input type="text" class="form-control totalSale" id="totalSaleAmountForRoti" name='totalSaleAmountForRoti' value="0" readonly>
    </td>

</tr>

<tr class="roti">
    column related class="form-control totalSale"
</tr>

What is the difference between them and their meaning?

var $class = $(this).parent().parent().attr('class');

1)

totalSale = $(this).parents('.' + $class).find('.totalSale');

2)

totalSale = $(this).parents('.' + $class).siblings('.' + $class + ':last').find('.totalSale');

And what meanings of this below code?

if ($(this).parent().siblings().children().hasClass('.totalSale')) { ... }