Grooveshark has found its way back onto iOS and Android devices — despite official bans by Apple and Google — with the launch of an HTML5 browser-based app on Wednesday.

Currently, more than 20 million registered listeners use the free music-streaming platform online. Grooveshark continues to face a slew of legal complaints. Over the years, major U.S. records labels including EMI, Universal, Sony and Warner Music Groups have sued Grooveshark for copyright infringement and royalty payments.

Both Google and Apple removed the app from its mobile stores for unspecified violations.

"With Apple and Android blocking us from app stores, we really had no options until this HTML5 release," founder Sam Tarantino tells Mashable. "The only way to block the HTML5 Grooveshark is if the Internet goes down."

With the new browser-based player, Grooveshark users can take the platform's 15-million-song catalog on the go.

On August 28, Grooveshark's official Android app was reinstated to the Google Play market after being removed in 2011. A few days later on August 31, the app vanished from Google Play once again.

"We submitted [a request], we got in and then they kicked us out again," Tarantino says. "It's a bit of a challenge. I'm not quite sure what policies we are violating since we model ourselves on YouTube."

Despite Grooveshark's legal troubles, the company based in Gainesville, Fla., says it's moving forward with what listeners and artists want — a mobile app. The HTML5 mobile play will be available for free to all registered users in the U.S. The music-streaming company plans to introduce a premium model product in the future.

"Grooveshark for mobile users will be initially free," Tarantino says. "We want to show mobile users what can be done with a web browser. As we grow on the tablet and mobile device ecosystem, at that point we will look at a premium model."

In the app, users will be able to play songs, create playlists and listen to genre stations. Grooveshark's vast appeal as a music player continues to be its massive music catalog including lesser-known bands and indie favorites, Tarantino says.

The platform is in the midst of rebranding itself as "the YouTube of music" for many reasons. Tarantino believes Grooveshark's most important role is as a music-discovery platform. It's also modeling its legal policies after the procedures on Google's video-sharing platform. Both companies comply with the requirements of the Digital Millennium Copyright Act and remove copyright-infringing content in a timely manner.

"We operate basically like YouTube," Tarantino says. "We base our policies around how they do it, where we get take downs, we have users upload and we have label deals all the time."

Anyone can go to Grooveshark.com and find free songs to listen to. Users can upload music onto the music-streaming platform. This tactic is beneficial for newer artists, Grooveshark says. Tarantino believes they're filling a hole that Myspace left with its demise. On Myspace, independent artists could potentially capture the hearts of millions of users.

"This fight is far from over and we're going to defend ourselves," Tarantino says. "We believe we're right and that we built a service benefitting hundreds of thousands of independent artists that have signed up for us and uploaded content."

Would you use a mobile browser-based music player? Tell us in the comments what you think about Grooveshark's new player.

Image courtesy of Grooveshark.