How to hide 1 block when opening another?

Question

css

I tried to write a code in JQuery that if one block has the display property equal to block, then the stroke of the other one disappears.

var $menutf = $('.navtf').css('display');
    if ($menutf == 'block') {
      $('header').css({
        "border": "0"
      });
    }

But doesn't work...

Answer 1

var menutf = $('.navtf');
if (menutf.is(':visible')) {
    $('header').css({
        "border": "0"
      });
}