$str = <<<S
<SCRIPT>18778</SCRIPT>
<SCRIPT>8787</SCRIPT>
<SCRIPT>228771</SCRIPT>
S;
preg_match_all("#<SCRIPT>(.+)</SCRIPT>#Uis",$str, $m);
print_r( $m );
<SCRIPT>18778</SCRIPT>
<SCRIPT>8787</SCRIPT>
<SCRIPT>228771</SCRIPT>
S;
preg_match_all("#<SCRIPT>(.+)</SCRIPT>#Uis",$str, $m);
print_r( $m );
<script.*?</script>关于非贪婪模式:(推荐)
http://www.regexlab.com/zh/regref.htm