使用正则表达式从字符串中提取正确的值

Question

我正在尝试解析youtube提供的数据，我们收到的数据很混乱，如下所示：var str1 = "sp=sig&s=VQ%3DQP9RU7Lk%3DNY8A2K77AqlhtQFHhgjwUKJ7AIJlMRFv3zAEiAOkJ3YA-44rCPLIGBJnwPdO0uj40Z7mljzZ2AXCvRi1KAhIgRww2IxgLALP&url=https%3A%2F%2Fr5---sn-cvh76nes.googlevideo.com%2Fvideoplayback%3Fexpire%3D1568300957%26ei%3DPQt6XY7IAve61Abrw6_wAQ%26ip%3D117.204.241.200%26id%3Do-ALVM4ikuXaCe79Biki6ND2_b9Tcbu8lq4-lMLv3LHEve%26itag%3D43%26source%3Dyoutube%26requiressl%3Dyes%26mm%3D31%252C26%26mn%3Dsn-cvh76nes%252Csn-h557sns7%26ms%3Dau%252Conr%26mv%3Dm%26mvi%3D4%26pl%3D24%26initcwndbps%3D200000%26mime%3Dvideo%252Fwebm%26gir%3Dyes%26clen%3D15541206%26ratebypass%3Dyes%26dur%3D0.000%26lmt%3D1567892283575963%26mt%3D1568279236%26fvip%3D5%26c%3DWEB%26txp%3D5511222%26sparams%3Dexpire%252Cei%252Cip%252Cid%252Citag%252Csource%252Crequiressl%252Cmime%252Cgir%252Cclen%252Cratebypass%252Cdur%252Clmt%26lsparams%3Dmm%252Cmn%252Cms%252Cmv%252Cmvi%252Cpl%252Cinitcwndbps%26lsig%3DAHylml4wRQIhAI3rDvKBNzfeh9dyIFzgVC0fZ4iloNfBwPuMRlZnKJnGAiAxEYb5hDuizUHBXub1TfLiEpE2JkKYA4PFeguH8izQmg%253D%253D";或这个：var str2 = "url=https%3A%2F%2Fr5---sn-cvh76nes.googlevideo.com%2Fvideoplayback%3Fexpire%3D1568301634%26ei%3D4g16XbD5JZ6H3LUP0d-WyAo%26ip%3D117.204.241.200%26id%3Do-AJq_yac4GJRrnb7CPAFTFaQqfK4NBUzepYOo07WdMVK9%26itag%3D18%26source%3Dyoutube%26requiressl%3Dyes%26mm%3D31%252C26%26mn%3Dsn-cvh76nes%252Csn-h557sns7%26ms%3Dau%252Conr%26mv%3Dm%26mvi%3D4%26pl%3D24%26initcwndbps%3D188750%26mime%3Dvideo%252Fmp4%26gir%3Dyes%26clen%3D11441933%26ratebypass%3Dyes%26dur%3D165.720%26lmt%3D1567716422140989%26mt%3D1568279980%26fvip%3D5%26c%3DWEB%26txp%3D6311222%26sparams%3Dexpire%252Cei%252Cip%252Cid%252Citag%252Csource%252Crequiressl%252Cmime%252Cgir%252Cclen%252Cratebypass%252Cdur%252Clmt%26lsparams%3Dmm%252Cmn%252Cms%252Cmv%252Cmvi%252Cpl%252Cinitcwndbps%26lsig%3DAHylml4wRQIhALYdxd4qwK4dT3-6pUN9Elb2jUHR9OZ2w-oaJ1fj5djdAiB_pGo5784Uhu0VKT9p6O366IyaQzKanI4seyKm1t-UaA%253D%253D&sp=sig&s=H%3D%3D%3Dgmz8buy%3Dhsmd9mFSGKhiwwvA2H