用不同的源代码替换源代码

I'm trying to build an artist website which has video uploaded in the website. I've used HTML 5 video to create a video player in my website. So, I've created a container for the video player and another wrapper for the video playlist. By default, the first video in the playlist will be played. In my playlist, I've added a play button, when you clicked at that button, then the source code from that section should be added in the video player's source code and the old source code should be removed and the new source code should play on the video player. I'm not sure how to replace the default source code with the new source code of the video.I'm trying to build an artist website which has