Php program line feed, how to write?

Php program line feed, how to write? Reply to discussion (solution)

\ R \ n

\ R \ n

The program is in the browser. it is a line break! ()
Why is the terminal command line? ()

Change:
The program is executed in the terminal command line. it is a line break! ()

Why is it a space character instead of a line break in the browser? ()

\ R \ n is text line feed

HTML line feed

\ R \ n is text line feed

HTML line feed

Php program, how to write a line feed?
To an instance!

Echo '100
';

$ X = array (1, 2, 3 );
Echo $ x [0];
Echo"
";
Echo $ x [1];
Echo"
";
Echo $ x [2];
Echo"
";
?>