Square DIV where height is equal to viewport

Question

I need to create a DIV where width=height, and height=100% of the viewport (which, obviously, is variable).

In other words, a perfectly sq

Answer 1

You can do this with jquery (or pure javascript if you prefer).

With jquery:

$(document).ready(function(){
  var height = $(window).height();
  $('#square').css('height', height);
  $('#square').css('width', height);
});