Numerous users of China's Weibo platform described the death of Jiang, who remained influential after finally retiring in 2004, as the end of an era.
Over half a million commenters flooded a post by state broadcaster CCTV announcing the death on the Twitter-like platform Weibo within an hour, with many referring to the late leader as "Grandpa Jiang".
"I'm very sad, not only for his departure, but also because I really feel that an era is over," a Henan
province-based user wrote.
"He represented our childhood and youth," another user said.
"As if what has happened wasn't enough, 2022 tells people in a more brutal way that an era is over," a Beijing Weibo user posted.
Some used Jiang's death -- announced after a weekend of protests across the country over President Xi Jinping's tough zero-Covid policy -- to take veiled jabs at China's current leader.
"The Jiang era, while not the most prosperous era, was a more tolerant one," one Weibo user wrote.
"I have heard many criticisms of him, but the fact that he allowed critical voices to exist shows how he is worthy of praise," wrote another.
Flags at major Chinese Communist Party and government buildings in China and worldwide will be flown half-mast after Jiang died.
The order, from Jiang's funeral arrangement committee, applies from Wednesday until the date of his funeral, yet to be announced, according to state broadcaster.
The online pages of state media sites including People's Daily and Xinhua turned to black and white in mourning.
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