This very Common Problem facing web developer. whenever user updating style sheet.
they need to press (Ctrl + F5) for clear browser cache.
Now if you are using any JavaScript file then give name like
for i.e
JavaScriptFileName.js?Math.random() <script type="text/javascript" src="http://hostname.net/js/JavaScriptFileName.js?Math.random()">
</script>
this is solution for clear browser cache.