javascript button onclick
// Here you can use getElementById
// or getElementByClassName or getElementByTagName...
// Example #1
document.getElementById("button").onclick = function() {
alert("Hello World!");
}
// Example #2
let obj = document.getElementsByClassName('button');
obj.addEventListener("click", function() {
// your code here...
});
// Example #3 (geting attributes)
let obj = document.getElementById("button")
obj.onclick = function() {
obj.style.display = "none";
// or:
// obj.style = "display: none; color: #fff"
}