<?php //\\2是一个后向引用的示例. 这会告诉pcre它必须匹配正则表达式中第二个圆括号(这里是([\w]+)) //匹配到的结果. 这里使用两个反斜线是因为这里使用了双引号. $html = "< b> bold text< /b> <img href=howdy.html> click me< /a>"; preg_match_all("/(< ([\w]+)[^> ]*> )(.*?)(< \/\\2> )/", $html, $matches, PREG_SET_ORDER); foreach ($matches as $val) { echo "matched: " . $val[0] . "\n"; echo "part 1: " . $val[1] . "\n"; echo "part 2: " . $val[2] . "\n"; echo "part 3: " . $val[3] . "\n"; echo "part 4: " . $val[4] . "\n\n"; } ?>