in IE, the "X-Requested-With" header of jquery becomes "x-requested-with" (lowercase)

Question

Why it is converting to lowercase? In Firefox it goes as: "X-Requested-With". While in IE, it goes as: "x-requested-with"

Answer 1

The HTTP method is supposed to be case-sensitive, but the HTTP headers are supposed to be case-insensitive, according to RFC 2616.