perl - Why do use `\n` in CGI script while printing header? -

in cgi script, on top program use the:

print "content-type: text/html\n\n"; 

without using \n not execute. but, inside html body, not use \n because \n can't make sense, new line use <br> tag.

why \n necessary in header line?

content-type: text/html http header, not html. detecting end of http header must 1 empty line. first \n end of current line, second \n new empty line.