On Windows, you can press ALT + an access key; on Macintosh, you can press Control + an access key. How about Unix/Linux? In W3Schools, it says that the value is character. It was worked when I define the access key in number. However, if the key is a letter(whether capital or lowercase), it seems useless. I have tried in many browsers, e.g. IE, Firefox, Opera, Maxthon, Netscape and Mozilla! Why?Can the access key define in letters? If yes, what is the difference in capital letters and small letters?