The white-space property controls how
whitespace is handled inside your text. "Whitespace" is basically a
collective term for:
the "space" character (Unicode code 32),
the "tab" character (Unicode code 9),
the "line feed" character (Unicode code 10),
the "carriage return" character (Unicode code 13) and
the "form feed" character (Unicode code 12)
This property can be one of the following 4 values:
normal
pre
nowrap
inherit
If you set it's value to normal your
web browser will collapse all whitespace automatically and only break
lines as necassary (or when you specify <br>).
If you set it's value to pre (which
stands for pre-formatted), your web browser will not collapse sequences
of whitespace, it will display your text exactly as you have written it in the source.
If you set it's value to nowrap, the only way you can
include a line break in your text is by including the <br> element.
All other whitespace will be collapsed.
If you set it's value to inherit
it will use the same white-space property value
as it's parent.
Read an
official description of the white-space property from the W3C