HTML form action method=“POST” or method=“post”? [duplicate]

Answer 1

from http://www.w3.org/TR/html5/syntax.html

Many strings in the HTML syntax (e.g. the names of elements and their attributes) are case-insensitive, but only for characters in the ranges U+0041 to U+005A (LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z) and U+0061 to U+007A (LATIN SMALL LETTER A to LATIN SMALL LETTER Z). For convenience, in this section this is just referred to as "case-insensitive".

Answer 2

From the w3c docs for forms:

Possible (case-insensitive) values are "get" (the default) and "post".

Answer 3

No difference! I always use lower case.