display html after click event code example

Example 1: how to detect a button click in javascript

if(document.getElementById('button').clicked == true)
{
   alert("button was clicked");
}

Example 2: how to add onclick event in javascript

var element = document.getElementById("elem");
element.onclick = function(event) {
  console.log(event);
}

Example 3: javascript onclick

var myElem = document.getElementByID('ElemID');
myElem.onclick = function() {
	//do stuff
}

Example 4: javascript onclick button

var button = document.querySelector('button');
button.onclick = function() {
  //do stuff
}