Javascript not working as planned

So i've been looking at this jquery plugin that highlights the current menu item depnding on the current page. I currently want the menu items border and text to change color. The CSS method i'm trying to achieve this in is .selected I'm probably being really silly here, however i can't seem to get it working. Any help would be really appreciated. My JS is countained in a seperate folder.

<script type="text/javascript" src="jquery-1.11.3.min.js"></script>
<script src="js/pageMenu.js" type="text/javascript" ></script>

<div class="container">
    <header class="site-header">
        <img id="logo" src="logo.png" alt="logo">
           <nav id="nav"<a href="#"></a>
       <ul id="site-nav">
        <li><a href="index.php">Home</a>
        </li>
         <li><a href="#">Used Cars</a>
         </li>
         <li><a href="aboutus.php">About us</a>
         </li>
         <li><a href="#">Contact Us</a>
       </li>
    </ul>
</nav>

Here is the JS

$(document).ready(function(){
$('#site-nav a').each(function(index) {
    if(this.href.trim() == window.location)
        $(this).addClass("selected");
  });
});

finally the CSS (which i know is a mess)

#site-nav {
margin: 0px;
padding: 0px;
line-height: 1;
}

#site-nav li {
float: left;
list-style: none;
}

#site-nav li a:link, #site-nav li a:visited {
font-family: 'Pontano Sans', sans-serif;
font-size:14px;
font-weight: bold;
display: block;
padding: 12px 17px;
text-decoration: none;
border-radius: 0px 0px 8px 8px;
/* horizontal radius / vertical radius */
list-style: none;
border-style: outset;
border-width: 1px;
background: #FFFFFF;
background: rgba(226, 226, 226, 1);
background: -moz-linear-gradient(top, rgba(226, 226, 226, 1) 0%, rgba(219,      219, 219, 1) 3%, rgba(209, 209, 209, 1) 51%, rgba(254, 254, 254, 1) 100%);
background: -webkit-gradient(left top, left bottom, color-stop(0%, rgba(226, 226, 226, 1)), color-stop(3%, rgba(219, 219, 219, 1)), color-stop(51%, rgba(209, 209, 209, 1)), color-stop(100%, rgba(254, 254, 254, 1)));
background: -webkit-linear-gradient(top, rgba(226, 226, 226, 1) 0%, rgba(219, 219, 219, 1) 3%, rgba(209, 209, 209, 1) 51%, rgba(254, 254, 254, 1) 100%);
background: -o-linear-gradient(top, rgba(226, 226, 226, 1) 0%, rgba(219, 219, 219, 1) 3%, rgba(209, 209, 209, 1) 51%, rgba(254, 254, 254, 1) 100%);
background: -ms-linear-gradient(top, rgba(226, 226, 226, 1) 0%, rgba(219, 219, 219, 1) 3%, rgba(209, 209, 209, 1) 51%, rgba(254, 254, 254, 1) 100%);
background: linear-gradient(to bottom, rgba(226, 226, 226, 1) 0%, rgba(219, 219, 219, 1) 3%, rgba(209, 209, 209, 1) 51%, rgba(254, 254, 254, 1) 100%);
filter: progid: DXImageTransform.Microsoft.gradient(startColorstr='#e2e2e2', endColorstr='#fefefe', GradientType=0);
}

 #site-nav a:focus, #site-nav a:hover {
color: #DC2F35;
background-color: #FFFFFF;
}
.selected {
color: #DC2F35;
border-color: #DC2F35;
}