How to change text on hover jquery

HTML

<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<a href="#" id="hoverelement">Hover Me</a>
<br/>
<span id="hover">asdsadsadsad</span>

JavaScript

$(document).ready(function(e) {
        $('#hover').hover(function(){
				$main_text=$('#hoverelement').text();
        $replacetext="dfdsfadsf";
				$('#hoverelement').text("This is a text on hover");
			},function(){
				$('#hoverelement').text($main_text);
				});
    });