How to stretch a block in a responsive template?

Question

css

How would you make up the next moment?

<section id="block_1">
<div class="myclass">...</div>
</section>
<section id="block_2"></section>

at a certain width, you need to stretch (move) the .myclass block to #block_2
It comes to mind only with the help of js for example appendTo (). Are there options without js?

Answer 1

Нет.

Answer 2

попробуй через jquery что ли, .width()