document.querySelector("#button").addEventListener("click", function(event) {

  console.log("click");

}, false);

document.querySelector("#button").addEventListener("mousedown", function(event) {

  console.log("mousedown");

}, false);

​

document.querySelector("#button").addEventListener("keypress", function(event) {

  var keyCode = event.keyCode || event.which;

  console.log("keypress");

}, false);