These are working in a JSFiddle that andi posted on the answer to my original question. I'm stumped as to what I've missed that it isn't working in the browser. I know this is going to be a very simple fix. Thanks in advance.
HTML:
<div class="blackwrap">
    <header class="blackbar">
        <h2>Before he knew it, he couldn't see a thing.</h2>
        <h4>He fumbled around for the <a id="flash">flashlight</a> on his phone.</h4>
    </header>
</div> <!-- .blackwrap-->    
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script src="script.js"></script>
</body>
CSS:
.blackbar {
    background: black;
    color: white;
}
.blackbar.lit {
    background:yellow;
    color:black;
}
Javascript:
$("#flash").on("mouseover", function(){
    $(".blackbar").addClass("lit");
}).on("mouseout", function(){
    $(".blackbar").removeClass("lit")
});
 
     
     
     
    
