Google has just hammered another nail in the coffin for Flash, Adobe's multimedia format widely criticised for its frequent security vulnerabilities.

Google has set deadlines for when it will stop running Flash ads and accept only those written in HTML5, the latest version of the Web's mother tongue.

As of June 30, Google will stop accepting new Flash-based display ads for AdWords and DoubleClick Digital Marketing. And Flash ads won't be allowed on the company's Display Network or DoubleClick after Jan. 2, 2017.

Flash is one of the most commonly targeted formats by hackers because it's installed on hundreds of millions of computers. Unpatched vulnerabilities can allow a hacker to install malicious software on a computer if a victim merely views a malicious ad.

Attackers also use social engineering to trick people into thinking their Flash program needs updating, and then deliver malicious downloads.

Apple founder Steve Jobs was among the first to take on Flash, forbidding it to run on the iPhone.

Last year, Facebook's chief security officer called on Adobe to retire Flash. Then in September, Google stopped automatically playing some Flash content on Web pages.

Adobe acknowledged in December that HTML5 was the future, saying it was even renaming its Flash Pro design and animation tool to Animate CC. This shipped with new features yesterday.