debugger.js

var events = 'click change focus'.split(' '), // add more as needed
    eLen = events.length,
    eI = 0,
    els = document.getElementsByTagName('*'),
    len = els.length,
    i = 0,
    el;

var debug_mode = 1;

for (; i < len; i++) {
    el = els[i];
    for (eI = 0; eI < eLen; eI++) {
        var event = el['on' + events[eI]];
        el['on' + events[eI]] = function() { if(!debug_mode) { event(); }; 
    }
}