Grid view header is fixed when run from localhost, but fails after hosting in IIS

I have grid view in aspx page . i have included the css to make it fixed on scroll.Its working fine when i run the application from the localhost (from visual studio ). , Its not working when i run the application after hosted in the IIS .
th { top: expression(document.getElementById("divDatagrid").scrollTop-2); z-index: 10 !important; }