title: Dynamic height of main block
body: <p>On the page, there are 3 blocks (header, main and footer). 4th (apple_ios_status_bar_background) is hidden by default and displayed (or hidden) dynamically in code. When this unit is not displayed, you can see all 3 blocks on the page. If the display 4th block - the block footer goes down the page. It is necessary that would block main changed its height dynamically (all blocks should always be visible on the page).</p>
  
  <p>Code <a href="https://jsfiddle.net/j3qm5qgx/1/" rel="nofollow noreferrer">https://jsfiddle.net/j3qm5qgx/1/</a></p>
  
  <p>In JS detect iOS system, if true - show <code>apple_ios_status_bar_background</code> block, hide if false.</p>
  
  <p><img src="https://i.stack.imgur.com/9s9d8.png" alt="enter image description here"></p>
  
  <p><img src="https://i.stack.imgur.com/guBcz.png" alt="enter image description here"></p>