Hello. I have form that contains an input field (Screen) whose name contains an upper-case letter.

Code HTML4Strict:
	<form action="http://localhost/example.php" method="get" name="form" id="form">
		<input value="medium" name="Screen" id="screen"/>
		<button name="upload" type="submit">Upload</button>
So when sent the query is composed as:


Although it works without problem, I want to ask that an upper-case in query string is valid or not?