Edit in JSFiddle

 $( document ).ready(function() {
        // bind a click event to the 'skip' link
        $(".skip").click(function(event){
    
            // strip the leading hash and declare
            // the content we're skipping to
            var skipTo="#"+this.href.split('#')[1];
    
            // Setting 'tabindex' to -1 takes an element out of normal 
            // tab flow but allows it to be focused via javascript
            $(skipTo).attr('tabindex', -1).on('blur focusout', function () {
    
                // when focus leaves this element, 
                // remove the tabindex attribute
                $(this).removeAttr('tabindex');
    
            }).focus(); // focus on the content container
        });
    });
<a href="#content" class="skip">Skip to content</a>
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<ul>
  <li><a class="active" href="#home">Home</a></li>
  <li><a href="#news">News</a></li>
  <li><a href="#contact">Contact</a></li>
  <li><a href="#about">About</a></li>
</ul>
<br/>
<br/>
<br/>
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 <div id="content"><p>
 This is the main content of the page! 
 </p>
 <p>
 Katharine Mary Adela Maddison, née Tindal (15 December 1862 – 12 June 1929), usually known as Adela Maddison, was a British composer of operas, ballets, instrumental music and songs. She was also a concert producer. She composed a number of French songs in the style of mélodies; for some years she lived in Paris, where she was a pupil, friend and possibly lover of Gabriel Fauré. Subsequently, living in Berlin, she composed a German opera which was staged in Leipzig. On returning to England she created works for Rutland Boughton's Glastonbury Festivals. (<a href='https://en.wikipedia.org/wiki/Adela_Maddison'>Wikipedia - Adela Maddison</a>)
 </p>
 <img src="https://upload.wikimedia.org/wikipedia/en/6/60/Adela_Maddison_in_The_Sketch_1910_Der_Talisman.JPG"/>
 </div>
  .skip {
        position: absolute;
        top: -1px;
        left: -1px;
        height: 1px;
        width: 1px;
        text-align: left;
        overflow: hidden;
        color: white;
    }
    
    a.skip:active, 
    a.skip:focus, 
    a.skip:hover {
        left: 0; 
        top: 0;
        width: auto; 
        height: auto; 
        overflow: visible; 
    }
    
    ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #333;
}

li {
    float: left;
}

li a {
    display: block;
    color: white;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
}

li a:hover {
    background-color: #111;