//启用javascript 日志功能var logger = log4javascript.getLogger("main");log4javascript.setEnabled(true);var appender = new log4javascript.InPageAppender();appender.layout.pattern = ‘%d{yyyy-MM-dd HH:mm:ss,SSS} [%c] %-5p - %m{1}%n‘;logger.addAppender(appender);//点击Ctrl键时显示/隐藏日志控制台document.onkeydown = function (evt) {    var VK_F9 = 120;    //兼容IE和Firefox获得keyBoardEvent对象    var evt = (evt) ? evt : ((window.event) ? window.event : "");    //兼容IE和Firefox获得keyBoardEvent对象的键值    var key = evt.keyCode ? evt.keyCode : evt.which;    if (evt.ctrlKey) {        if (appender.visible) {            appender.hide();            appender.visible = false;            log4javascript.setEnabled(false);        } else {            log4javascript.setEnabled(true);            appender.show();            appender.visible = true;        }    }};

<script src="http://www.mamicode.com/~/Content/Third/log4javascript-1.4.2/log4javascript.js"></script><script src="http://www.mamicode.com/~/Scripts/Common/log4jsService.js"></script>

  $(function () {        $("#Button1").click(function () {            logger.debug("This is a debugging message from the log4javascript in-page page");            logger.info("info info");            logger.error("error info");        });    });