stacktrace.js

// this is the code available in the page
        var DEBUG_LOG = (function () {
            var timer = null, timeout = 5000;
            var head;

            return {
                add: function (item) {
                    head = { value: item, next: head };
                    if (timer) {
                        clearTimeout(timer);
                    }
                    timer = setTimeout(function () {
                        timer = null;
                        head = null;
                    }, timeout);
                },
                get: function () {
                    var a = [], item = head;
                    if (!item) return a;
                    do {
                        a.push(item.value);
                        item = item.next;
                    } while (item);
                    return a;
                },
                getStacktrace: function () {
                    var a = [], item = head;
                    if (!item) return a;

                    var toString = Object.prototype.toString;
                    do {
                        var args = [], arg, value, type;
                        // loop over the arguments
                        for (var i = 0, len = item.value.arguments.length; i < len; i++) {
                            value = item.value.arguments[i];
                            type = toString.call(value).substring(8);
                            type = type.substring(0, type.length - 1);
                            switch (type) {
                                case "Function":
                                    value = "fn:" + (value.name || /function\s([\w$]+)\(/.exec(value.toString())[1]);
                                    break;
                                case "String":
                                    value = "'" + value + "'";
                                    break;
                                case "Number":
                                case "Boolean":
                                case "RegExp":
                                    break;
                                default:
                                    value = type;
                            }

                            args.push(value);
                        }
                        a.push((item.value.fn.name || /function\s([\w$]+)\(/.exec(item.value.fn)[1]) + "(" + args.join(",") + ")");
                        item = item.next;
                    } while (item);
                    return a;
                }
            };
        } ());

// then the rewrite engine rewrites all /function [\w$]+\(.+?\{/ patterns adding 'DEBUG_LOG({fn:arguments.callee, arguments: arguments});
function foo(bar){
..
// becomes
function foo(bar){DEBUG_LOG({fn:arguments.callee, arguments: arguments})
...

// The listould easily be extended to have max number of items, but for my project I opted for using time and any sequence of actions lasting more than 5 seconds is recorded. 

// When you want to use the stacktrace just call 
DEBUG_LOG.getStacktrace();