Plain jQuery binding function is getting called twice for me, I have seen this problem when working with jQuery mobile also.
$(document).ready(function(){
$(window).bind("resize",function(){
$("#length").text($(window).width());
$("#length").show("slow");
$("#length").hide("slow");
});
});
<html>
<body>
<div id='length' style= display:none></div>
<div class="font size">1</div>
</body>
</html>
fiddled : http://jsfiddle.net/2Yy7Q/