>>101242070
addEventListener expects a function. You will have to write one.
div1.addEventListener("click", () => changeInnerHtml("div1"));
or
function doTheThing() {
changeInnerHtml("div1");
}
div1.addEventListener("click", doTheThing);
or
div1.addEventListener("click", function doTheThing() {
changeInnerHtml("div1");
});