This function will turn output buffering on. While output buffering
is active no output is sent from the script, instead the output
is stored in an internal buffer.
The contents of this internal buffer may be copied into a string
variable using ob_get_contents(). To output
what is stored in the internal buffer, use
ob_end_flush(). Alternatively,
ob_end_clean() will silently discard the
buffer contents.
