// http://jsfiddle.net/s1o8a335/
window.addEventListener("load", load_handler);
document.body.addEventListener("click", click_handler);

function load_handler(evt) {
    logEvent(evt);
    document.body.click();
}
function click_handler(evt) {
    logEvent(evt);
}
function logEvent(evt) {
    var output = document.getElementById("log");
    var logLines = [
        ["Event name", evt.type],
        ["InstanceOf Event", evt instanceof Event],
        ["InstanceOf UIEvent", evt instanceof UIEvent],
        ["InstanceOf MouseEvent", evt instanceof MouseEvent],
        ["toString", evt.toString()]
    ].map(function (arr) { return arr.join(": "); });
    output.innerHTML += logLines.join("<br>") + "<br><br>";
}