More than $1.8 million has been raised online in less than a day for the slain Robb Elementary School teacher whose husband then died of a broken heart.

The GoFundMe was launched to raise money for the four children of Irma Garcia — one of two teachers slain alongside their 19 young students — and her husband of 24 years, Joe, who died of a heart attack Thursday.

“I truly believe Joe died of a broken heart and losing the love of his life of more than 25 years was too much to bear,” confirmed Debra Austin, one of Irma Garcia’s cousins who started the fundraiser Thursday.

Her cousin Irma “loved her classroom kids and died trying to protect them,” she wrote.

It had sought just $10,000, but quickly collected more than 180 times that much after donations from nearly 30,000 people Friday.

By Friday morning, the fundraiser had collected $1,819,500 for the family of the couple, whose kids ranged in age from 12 to 23.

GoFundMe’s top 12 fundraisers early Friday are all for the Uvalde massacre — save for $1.9 million raised for the 10 people shot dead in a supermarket in Buffalo, New York, just 10 days earlier.

A main “Texas Elementary School Shooting Victims Fund” had raised $3,654,960 by Friday thanks to donations from more than 54,000 people.

It was set up by VictimsFirst, the network of families devastated by earlier mass shootings. The group said it “started this fund to make sure that 100% of what is collected goes DIRECTLY to the victim base so the victims’ families and those wounded/injured.”

“We vowed this would never happen again,” they said, promising that “funds collected will go to the families in cash payments with no strings attached are protected from fraud and exploitation.”

Seven of the other top 12 fundraisers were for some of the 19 kids killed in Robb Elementary School on Tuesday by 18-year-old monster Salvador Ramos.

Another collection for the other slain teacher, Eva Mireles — whose sister called her “truly the definition of a hero” — had raised more than $90,000 by Friday.