Okay so I am learning jQuery now and I cannot find where I have gone wrong 

This is the tutorial video: https://www.youtube.com/watch?v=jIZFHjkUCrs&list=PL6B08BAA57B5C7810&index=24

In my (index.html) file I have 

<!DOCTYPE html>
<meta charset="utf-8"/>
<title>Learning to Create Websites</title>
<link rel="stylesheet" type="text/css" href="main.css"/>
<input id="search_name" type="text" name="text"/>
<ul id="names">

<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript" src="js/index.js"></script>

In (index.js)

search_name = $(this).val();
$("#names li: contains('" + search_name + "')").addClass('highlight');

in (main.css)
background-color: yellow;

I can't seem to get my file to work, thanks for the help in return.