Nav = navigator.appName;
if(Nav == 'Microsoft Internet Explorer'){
NavCSS = 'main_ie';
};
if(Nav == 'Netscape'){
NavCSS = 'main_data';
}
else {
NavCSS = 'main_data';
};
document.write('<link rel="stylesheet" type="text/css" href="sheets/css/' + NavCSS + '.css" />');