ContentScripts需要使用Match Pattern来确定对哪些页面起作用。

    一个合法的match pattern可能是all_urls（代表所有url），或者是一个带有*号的url。这个url的生成规则如下： 

    1. <url-pattern> := <scheme>://<host><path> 
    2. <scheme> := '*' | 'http' | 'https'  
    3. <host> := '*' | '*.' <any char except '/' and '*'>+ 
    4. <path> := '/' <any chars>

    需要注意的地方是scheme中只能是或者http、https，而不能是tps这类的，而且在这里只能代替http和https，对ftp或者其他scheme无效。host中也是一样，用到的话，只能是,或者.xxx.com这类的，而不能是test..com这样的。只能出现在host的最前面。

    例子下面是一些正确的Pattern和一些错误的，取自chrome的extension文档，针对我们的差异稍作修改。

    Pattern What it does Examples of matching URLs
    http:/// Matches any URL that uses the http schemehttp://www.google.com/http://example.org/foo/bar.html
    http:///foo Matches any URL that uses the http scheme, on any host, as long as the path starts with /foohttp://example.com/foo/bar.htmlhttp://www.google.com/foo
    https://.google.com/foobar Matches any URL that uses the https scheme, is on a google.com host (such as www.google.com, docs.google.com, or google.com), as long as the path starts with /foo and ends with barhttp://www.google.com/foo/baz/barhttp://docs.google.com/foobar
    http://example.org/foo/bar.html row 2, cell 2 row 2, cell 3
    http://127.0.0.1/* row 2, cell 2 row 2, cell 3
    ://mail.google.com/ Matches any URL that starts with http://mail.google.com or https://mail.google.com.http://mail.google.com/foo/baz/barhttps://mail.google.com/foobar
    all_urls Matches any URL that uses a permitted scheme. (See the beginning of this section for the list of permitted schemes.)http://example.org/foo/bar.html

    Here are some examples of invalid pattern matches:

    Bad pattern Why it's bad
    http://www.google.com No path
    http://*foo/bar '' in the host can be followed only by a '.' or '/'
    [http://foo..bar/baz](http://foo.*.bar/baz) If '' is in the host, it must be the first character
    http:/bar Missing scheme separator ("/" should be "//")
    foo:// Invalid scheme