jslogger

            (function(){

                var logger = {};
                //绑定键盘
                var bPressAlt = false;
                var st;


                function getOs(){
                    var OsObject = "";
                    if (navigator.userAgent.indexOf("MSIE") > 0) {
                        return "MSIE";
                    }
                    if (isFirefox = navigator.userAgent.indexOf("Firefox") > 0) {
                        return "Firefox";
                    }
                    if (isSafari = navigator.userAgent.indexOf("Safari") > 0) {
                        return "Safari";
                    }
                    if (isCamino = navigator.userAgent.indexOf("Camino") > 0) {
                        return "Camino";
                    }
                    if (isMozilla = navigator.userAgent.indexOf("Gecko/") > 0) {
                        return "Gecko";
                    }

                }

                logger.init = function(){

                    var div = document.createElement("div");
                    div.style.cssText = 'position:absolute;right:0px;top:0px;width:300px;height:250px;z-index:1;	background-color: #000;	';
                    div.id = "loggerBox";
                    div.innerHTML = '<div id="loggerBox_Conver"style="background:#CCCCCC" ><button>clear</button></div><div id="loggerBox_Container"></div>';
                    document.body.appendChild(div);

                    document.getElementById("loggerBox_Container").style.cssText = "position:absolute;width:100%;height:230px;overflow:auto;overflow-x:hidden";

                    document.onkeydown = function(e){
                        e = e || window.event;

                        if (e.keyCode === 16) {
                            bPressAlt = true;
                            st = new Date().getTime();
                            return;
                        }
                        var et = new Date().getTime();
                        if (e.keyCode === 73 && bPressAlt && st != null) {

                            if (et - st < 200) {

                                document.getElementById("loggerBox").style.display = "";
                                st = et;
                                bPressAlt = false;
                            }

                        }
                        else 
                            if (e.keyCode === 85 && bPressAlt && st != null) {

                                if (et - st < 200) {
                                    document.getElementById("loggerBox").style.display = "none";
                                    st = et;
                                    bPressAlt = false;
                                }

                            }

                        et = st = null;
                    }


                    document.getElementById("loggerBox_Conver").getElementsByTagName("BUTTON")[0].onclick = function(){

                        var childs = document.getElementById("loggerBox_Container").childNodes;
                        var j = childs.length;
                        for (var i = 0; i < j; i++) 
                            document.getElementById("loggerBox_Container").removeChild(childs[0]);
                    }

                }

                logger.info = function(txt){
                    var div = document.createElement("div");

                    if (getOs() == "Firefox") 
                        div.textContent = txt;
                    else 
                        div.innerText = txt;
                    div.style.color = "yellow";
                    document.getElementById("loggerBox_Container").appendChild(div);
                }


                window.logger = logger;



            })();

使用方法 shift+i 打开 shift+u 关闭

window.onload = function(){

                //初始化
                logger.init();


                logger.info(1);
                logger.info(1);
                logger.info(1);
                logger.info(1);
                logger.info(1);
                logger.info(1);
                logger.info(1);
                logger.info(1);
                logger.info(1);
                logger.info(11);



            }