Answers for "how to make onclick function in javascrip"

javascript onclick

document.getElementById("myBtn").addEventListener("click", function() {
  alert("Hello World!");
});

javascript button onclick

document.getElementById('button').onclick = function() {
   alert("button was clicked");
};

html js button onclick

// In HTML:
// <button id="buttonID" onclick="yourJSFunction()">Text</button>

// In JavaScript:
function yourJSFunction() {
  // Do stuff
 }