<!-- 空超鏈接 --><a href=""></a> <!-- 空白符 --><a href=" " rel="external nofollow" > </a><!-- a標簽含有其它屬性 --><a href="index.html" rel="external nofollow" rel="external nofollow" rel="external nofollow" $absolute = ''; // 去除所有的 './' $absolute = preg_replace('/(?<!/.)/.///','',$relative); $count = preg_match_all('/(?<!//)//([^//]{1,}?)///././//',$absolute,$res); // 迭代去除所有的 '/abc/../' do { $absolute = preg_replace('/(?<!//)//([^//]{1,}?)///././//','/',$absolute); $count = preg_match_all('/(?<!//)//([^//]{1,}?)///././//',$absolute,$res);  }while($count >= 1); // 除去最后的 '/..' $absolute = preg_replace('/(?<!//)//([^//]{1,}?)///./.$/','/',$absolute); $absolute = preg_replace('////./.$/','',$absolute); // 除去存在的 '../' $absolute = preg_replace('/(?<!/.)/././//','',$absolute); return $absolute;}$relative = 'http://www.mytest.org/../a/.../../b/c/../d/..';var_dump(url_to_absolute($relative));// 輸出：string 'http://www.mytest.org/a/b/' (length=26)