internet problem

i have develop a system, e-leave system. the problem is when using mozilla firefox 3.5 above, the menu bar of the system is gone. when using internet explorer 8, cannot click some certain button. could somebody help me. there is the coding:

function MM_reloadPage(init) { //reloads the window if Nav4 resized
if (init==true) with (navigator) {if ((appName==”Netscape”)&&(parseInt(appVersion)==4)) {
document.MM_pgW=innerWidth; document.MM_pgH=innerHeight; onresize=MM_reloadPage; }}
else if (innerWidth!=document.MM_pgW || innerHeight!=document.MM_pgH) location.reload();
}
MM_reloadPage(true);