title: How do i get a full image as background of my header in html/css?
body: <p>When i choose a image to put as a background of my div i can't manage to make it look normal. The width and height of my header are made with em. Can someone explain me how i can get a image as a background at my header when the header is like: 120em width. 5em height. So i need to make a normal header background the size of my header.</p>
  
  <pre><code>.header{
   -webkit-background-size: cover;
    -moz-background-size: cover;
   -o-background-size: cover;
   background-size: cover;
  background-image:url('images.jpg');
  text-align: center;
  width: 120em;
  height:5em;
  background-size:100%;
  }
  
  .left{
  background-color:red;
  float: left;
  width: 20em;
  height: 51em;
  }
  
  .middle{
  background-color: green;
  width:120em;
  padding:0px;
  margin:0px;
  height:51em;
  }
  
  .footer{
  height:4em;
  width: 120em;
  background-color: blue;
  }
  </code></pre>