Take the 2-minute tour ×  Is it possible to replace newlines
with the <br> tag, but to ignore newlines that follow a </h1>
tag?  So for example I want to change this block:  <h1>Test</h1>
\n some test here \n and here  To this:  <h1>Test</h1> some test
here <br /> and here share|improve this question Why would you
have that kind of code at the first place? It just seems that
your orginal situation itself is a problematic. –  newbie Mar 5
'10 at 22:17 add comment  2 Answers  up vote 1 down vote
accepted $subject = "<h1>hithere</h1>\nbut this other\nnewline
should be replaced."; $new =
preg_replace("/(?<!h1\>)\n/","<br/>",$subject); echo $new;  //
results in: // <h1>hithere</h1> // but this other<br/>newline
should be replaced.  Should work. This says \n not preceeded
immediately by h1>  share|improve this answer add comment  Using
string functions instead of regular expressions, and assuming
the </h1> tag can be anywhere on the line (instead of just
before the newline):  foreach ($lines as $line) {   if (stris