【jQuery】Technique to display background image in full window size using .height() | Demo page

.wrap {
  width: 100%;
}
.img {
  width: 100%;
  background: url("/img/a.jpg") no-repeat center;
  background-size: cover;
}
.block {
  height: 300px;
  text-align: center;
}
  

$(function(){
  var $window = $(window);
  var kvfull = $(".img");
  function Resize(){
    var winH = $window.height();
    kvfull.height(winH);
  }
  $window.on("resize",Resize);
  Resize();
});