This function is identical to ereg_replace() except that this ignores case distinction when matching alphabetic characters.
A POSIX extended regular expression.
If pattern contains parenthesized substrings,
replacement may contain substrings of the form
\\, which will be
replaced by the text matching the digit'th parenthesized substring;
\\0 will produce the entire contents of string.
Up to nine substrings may be used. Parentheses may be nested, in which
case they are counted by the opening parenthesis.
The input string.
The modified string is returned. If no matches are found in string, then it will be returned unchanged.
$pattern = '(>[^<]*)('. quotemeta($_GET['search']) .')';
$replacement = '\\1<span class="search">\\2</span>';
$body = eregi_replace($pattern, $replacement, $body);