The Interpreters, a romantic TV series, attracted millions of viewers before it recently went off air. It was adapted from an online novel published a decade ago by former interpreter Miao Juan, who sold the book's copyright to Croton Media, a Chinese company, in 2012.

Some of last year's TV hits - Ode to Joy, Nirvana in Fire and The Journey of Flower - were all based on online novels. In addition, Mojin: The Lost Legend made 1.6 billion yuan ($240 million) and The Left Ear 484 million yuan at the Chinese box office in 2015.

More than 100 TV and web series will be adapted from online books later this year, according to data analyzer Guduo Media, which tracks corporate announcements.

There is a surge in online writing in China as is evident from the number of small and big screen adaptations.

"Online writing here is mostly genre fiction, which is already mature in the West," Shao Yanjun, an associate professor of Chinese literature at Peking University, told China Daily.

General writers are turning to the internet to publish their works and gain popularity, partly due to lengthy procedures offline publishing, she said.

There are 1.4 million Chinese novels on qidian.com, owned by Yuewen Group, the country's largest online publishing company, while only around 70,000 such books are on the China site of Amazon, according to iResearch, a market-research company.

Luo Li, vice-president of the Yuewen Group, estimated that on their various websites there are 4 million registered writers, and there are 600 million registered users.

However, the registration process is simple and one person could have more than one ID on the websites.

"We hope to exploit the opportunity better with our partners ... not only through TV series and films but also video games, animation, plays and theme parks," he said of the future.

Liu Chang, who has been writing online sci-fi under the pen name Biting Dog, since 2012, said he is seeking a copyright price of 2 million yuan for one of his novels Global Evolution from a Chinese TV production house that wants to adapt it for the screen.

The fantasy writer Wei Lijun stood at 8th place in a 2015 rich list for Chinese online authors, with earnings of 15 million yuan in royalties. He writes mostly time-travel historical stories, and has millions of readers on qidian.com. Braveness of the Ming, a TV series based on one of his novels, may be released later in the year.

But not all online writers are making big money.

Zeng Dengke, who writes historical fantasy books under the name Crazy Banana, for instance, said the copyright of his works are owned by qidian.com.

"The current copyright procurement craze doesn't affect me," said Zeng, adding that top online authors fetch higher prices.

But he is positive that as TV adaptations of online literature grow, his work will be valued by people.

Besides TV series, many online novels are adapted into series that are only broadcast online. The web series attract a large viewership because mobile and tablet devices are a major channel for entertainment in China. The country has nearly 700 million online users.

"The emergence of web series generates a great demand for good scripts, and the number of scriptwriters in China can't keep pace," said Liu Yeyuan, deputy director of the TV series research center at Beijing's Communication University of China.

"So they turn to online novels that have already gathered a sizable readership and can guarantee similar viewership."

But Liu also cautions against rushing into copyright procurements of online novels as not all novels with large readerships are suitable for small and big screen adaptations.