How to play YouTube on the background of iPhone?

I want to hear music and search things on google on a different page on my iPhone 3G. Is it possible? Like hearing the audio playing while I'm on google on a website or something. Or can you only do that on iPhone 5s?

It's not possible with the youtube app. But on the App Store, search "PlayTube". You can play a video or song, and you can close the app and it'll keep playing in the background.

I thinnk you can only do that with the galaxy s3 and its only videos in your gallery not youtube videos