Answers for "using click event in javascript"

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
    };
};

javascript button click event

<element onclick="functionToExecute()">Click</element>