JAVASCRIPT

button click javascript

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

js click on button

window.onload = function() {
    var userImage = document.getElementById('imageOtherUser');
    var hangoutButton = document.getElementById("hangoutButtonId");
    userImage.onclick = function() {
       hangoutButton.click(); // this will trigger the click event
    };
};

element clicked js

document.addEventListener('click', function(e) {
    e = e || window.event;
    var target = e.target || e.srcElement,
        text = target.textContent || target.innerText;   
}, false);