Browser detection and compliancy

[wxdqz]

Hi there,

I am a newbee to JS, so sorry if my question sounds stupid...
I wanna use browser detection and so on, but I do not know if there are some compliancy problems, e.g. if some "attributed" would not be reconized by all browsers.

Below is the list of attributes I'd like to use; could someone tell me if some of them are not reconized by/compliant with some browsers?

window.screen.colorDepth;
window.screen.width;
window.screen.height;
window.screen.availWidth;
window.screen.availHeight;
window.screen.fontSmoothingEnabled;
window.screen.colorDepth;
navigator.javaEnabled();
navigator.appName;
navigator.appVersion;
navigator.appCodeName;
navigator.platform;

ANd how can I make error handling in JS?
If "window.screen.fontSmoothingEnabled" is not reconized by IE3.0 for instance, would this line of code prevent the error message from appearing:
if(!window.screen.fontSmoothingEnabled) { ...//not reconized, then assign a default value
?

Thanks in advance for any help, could not find any answer on tutorials about that till now...