var str = 'http://a.com/b/c.php?s=/Search/index.html';
str.match(/(?!\?s=\/)\w+?(?=\/index\.html)/g);

// ["Search"]

//如果地址是这样的：
var str = 'http://a.com/b/c.php?s=/Search/a/b/index.html';
str.match(/(?!\?s=\/)[\w\/]+?(?=\/index\.html)/gi);

//["/Search/a/b"]

location.search.split('/')[1]

看看正则方法 截取 特定位置