SAN FRANCISCO — Online document-sharing site Scribd is looking to Netflix’s success story as it sets out to create the world’s largest subscription service for digital books.

The opening chapter in Scribd’s quest begins Tuesday with the introduction of an e-book subscription service that will boast thousands of titles published by HarperCollins before July 2012. HarperCollins, which is owned by News Corp., becomes the first of the five largest U.S. publishers to join a service vying to create an alternative to buying individual titles.

Scribd will charge $9 per month for a service that offers unlimited access to most of HarperCollins’ back catalog, as well as an assortment of other books from smaller publishers. Recent best-sellers from Harper Collins aren’t included in the subscription service, although customers will be able to buy new titles individually on Scribd’s site.

“I feel we are moving into new uncharted waters, but that’s what innovating and reading is all about,” HarperCollins CEO Brian Murray said in an interview.

With their personal log-in, subscribers throughout the world will be able to browse through books using Apple Inc.’s iPhone and iPad, mobile devices running on Google Inc.’s Android software and any personal computer with a Web browser.