Most browsers typically use any whitespace as a separator (1 or more whitespaces is treated the same as just one). It should not matter to the browser if there are no line breaks or carriage returns.
While we cannot speak for all browsers and how they are implemented, let's look at the HTML 4 spec, Section 9.1 for whitespace:
Note that a sequence of white spaces between words in the source
document may result in an entirely different rendered inter-word
spacing (except in the case of the PRE element). In particular, user
agents should collapse input white space sequences when producing
output inter-word space. This can and should be done even in the
absence of language information (from the lang attribute, the HTTP
"Content-Language" header field (see [RFC2616], section 14.12), user
agent settings, etc.).
The PRE element is used for preformatted text, where white space is
So in the vast majority of cases, if the browser is complaint with the spec, then it should render it how the spec describes (of course, the browser vendors have been known to use creative interpretation over time.)