“控制台”是InternetExplorer的未定义错误。-'console'isundefinederrorforInternetExplorer

370  

Try

试一试

if (!window.console) cOnsole= ...

An undefined variable cannot be referred directly. However, all global variables are attributes of the same name of the global context (window in case of browsers), and accessing an undefined attribute is fine.

未定义的变量不能直接引用。但是，所有全局变量都是全局上下文的相同名称的属性(在浏览器中是窗口)，并且访问未定义的属性是好的。

Or use if (typeof cOnsole=== 'undefined') cOnsole= ... if you want to avoid the magic variable window, see @Tim Down's answer.

或者使用if(控制台== 'undefined')控制台=……如果您想要避免神奇的变量窗口，请参见@Tim Down的答案。

312  

Paste the following at the top of your Javascript (before using the console):

在Javascript的顶部粘贴以下内容(在使用控制台之前):

/**
 * Protect window.console method calls, e.g. console is not defined on IE
 * unless dev tools are open, and IE doesn't define console.debug
 * 
 * Chrome 41.0.2272.118: debug,error,info,log,warn,dir,dirxml,table,trace,assert,count,markTimeline,profile,profileEnd,time,timeEnd,timeStamp,timeline,timelineEnd,group,groupCollapsed,groupEnd,clear
 * Firefox 37.0.1: log,info,warn,error,exception,debug,table,trace,dir,group,groupCollapsed,groupEnd,time,timeEnd,profile,profileEnd,assert,count
 * Internet Explorer 11: select,log,info,warn,error,debug,assert,time,timeEnd,timeStamp,group,groupCollapsed,groupEnd,trace,clear,dir,dirxml,count,countReset,cd
 * Safari 6.2.4: debug,error,log,info,warn,clear,dir,dirxml,table,trace,assert,count,profile,profileEnd,time,timeEnd,timeStamp,group,groupCollapsed,groupEnd
 * Opera 28.0.1750.48: debug,error,info,log,warn,dir,dirxml,table,trace,assert,count,markTimeline,profile,profileEnd,time,timeEnd,timeStamp,timeline,timelineEnd,group,groupCollapsed,groupEnd,clear
 */
(function() {
  // Union of Chrome, Firefox, IE, Opera, and Safari console methods
  var methods = ["assert", "cd", "clear", "count", "countReset",
    "debug", "dir", "dirxml", "error", "exception", "group", "groupCollapsed",
    "groupEnd", "info", "log", "markTimeline", "profile", "profileEnd",
    "select", "table", "time", "timeEnd", "timeStamp", "timeline",
    "timelineEnd", "trace", "warn"];
  var length = methods.length;
  var cOnsole= (window.cOnsole= window.console || {});
  var method;
  var noop = function() {};
  while (length--) {
    method = methods[length];
    // define undefined methods as noops to prevent errors
    if (!console[method])
      console[method] = noop;
  }
})();

The function closure wrapper is to scope the variables as to not define any variables. This guards against both undefined console and undefined console.debug (and other missing methods).

函数闭包包装器是对变量进行范围界定，而不是定义任何变量。此守护程序针对未定义的控制台和未定义的console.debug(和其他丢失的方法)。

EDIT: I noticed that HTML5 Boilerplate uses similar code in its js/plugins.js file, if you're looking for a solution that will (probably) be kept up-to-date.

编辑:我注意到HTML5 Boilerplate在其js/插件中使用了类似的代码。js文件，如果你正在寻找一个可以保持最新的解决方案。

72  

Another alternative is the typeof operator:

另一种选择是:

if (typeof cOnsole== "undefined") {
    this.cOnsole= {log: function() {}};
}

Yet another alternative is to use a logging library, such as my own log4Javascript.

另一种选择是使用日志库，比如我自己的log4Javascript。

46  

For a more robust solution, use this piece of code (taken from twitter's source code):

对于一个更健壮的解决方案，使用这段代码(取自twitter的源代码):

// Avoid `console` errors in browsers that lack a console.
(function() {
    var method;
    var noop = function () {};
    var methods = [
        'assert', 'clear', 'count', 'debug', 'dir', 'dirxml', 'error',
        'exception', 'group', 'groupCollapsed', 'groupEnd', 'info', 'log',
        'markTimeline', 'profile', 'profileEnd', 'table', 'time', 'timeEnd',
        'timeStamp', 'trace', 'warn'
    ];
    var length = methods.length;
    var cOnsole= (window.cOnsole= window.console || {});

    while (length--) {
        method = methods[length];

        // Only stub undefined methods.
        if (!console[method]) {
            console[method] = noop;
        }
    }
}());

13  

In my scripts, I either use the shorthand:

在我的脚本中，我要么使用速记:

window.console && console.log(...) // only log if the function exists

or, if it's not possible or feasible to edit every console.log line, I create a fake console:

或者，如果不可能编辑每个控制台。日志行，我创建了一个假控制台:

// check to see if console exists. If not, create an empty object for it,
// then create and empty logging function which does nothing. 
//
// REMEMBER: put this before any other console.log calls
!window.console && (window.cOnsole= {} && window.console.log = function () {});

10  

You can use console.log() if you have Developer Tools in IE8 opened and also you can use the Console textbox on script tab.

如果您在IE8中有开发工具，也可以在script选项卡上使用控制台文本框，那么您可以使用console.log()。

7  

if (typeof cOnsole== "undefined") {
  this.cOnsole= {
    log: function() {},
    info: function() {},
    error: function() {},
    warn: function() {}
  };
}

6  

In IE9, if console is not opened, this code:

在IE9中，如果没有打开控制台，则该代码:

alert(typeof console);

will show "object", but this code

将显示“对象”，但此代码?

alert(typeof console.log);

will throw TypeError exception, but not return undefined value;

将抛出TypeError异常，但不返回未定义值;

So, guaranteed version of code will look similar to this:

因此，有保证的代码版本看起来类似于:

try {
    if (window.console && window.console.log) {
        my_console_log = window.console.log;
    }
} catch (e) {
    my_console_log = function() {};
}

6  

I am only using console.log in my code. So I include a very short 2 liner

我只是使用控制台。登录我的代码。所以我包括了一个非常短的2号班轮。

var cOnsole= console || {};
console.log = console.log || function(){};

6  

Based on two previous answers by

根据之前的两个答案。

• Vinícius Moraes
• 维尼·莫拉
• Peter Tseng
• 彼得曾

and the documentations for

和文件

• Internet Explorer (IE 10)
• Internet Explorer(IE 10)
• Safari (2012. 07. 23.)
• Safari(2012。07年。23)。
• Firefox (2013. 05. 20.)
• Firefox(2013。05。20)。
• Chrome (2013. 01. 25.) and Chrome (2012. 10. 04.)
• Chrome(2013。01。25)和铬(2012。10。04)。
• and some of my knowledge
• 还有我的一些知识。

Here's a best effort implementation for the issue, meaning if there's a console.log which actually exists, it fills in the gaps for non-existing methods via console.log.

这里是这个问题的最佳实现，这意味着如果有控制台的话。日志实际上是存在的，它通过console.log来填补非现有方法的空白。

For example for IE6/7 you can replace logging with alert (stupid but works) and then include the below monster (I called it console.js): [Feel free to remove comments as you see fit, I left them in for reference, a minimizer can tackle them]:

例如，对于IE6/7，你可以用alert(愚蠢的但有效的)来代替日志记录，然后包括下面的怪物(我叫它console.js):(在你认为合适的时候可以随意删除注释，我把它们留给了参考，一个最小化器可以处理它们):

and console.js:

和console.js:

    /**
     * Protect window.console method calls, e.g. console is not defined on IE
     * unless dev tools are open, and IE doesn't define console.debug
     */
    (function() {
        var cOnsole= (window.cOnsole= window.console || {});
        var noop = function () {};
        var log = console.log || noop;
        var start = function(name) { return function(param) { log("Start " + name + ": " + param); } };
        var end = function(name) { return function(param) { log("End " + name + ": " + param); } };

        var methods = {
            // Internet Explorer (IE 10): http://msdn.microsoft.com/en-us/library/ie/hh772169(v=vs.85).aspx#methods
            // assert(test, message, optionalParams), clear(), count(countTitle), debug(message, optionalParams), dir(value, optionalParams), dirxml(value), error(message, optionalParams), group(groupTitle), groupCollapsed(groupTitle), groupEnd([groupTitle]), info(message, optionalParams), log(message, optionalParams), msIsIndependentlyComposed(oElementNode), profile(reportName), profileEnd(), time(timerName), timeEnd(timerName), trace(), warn(message, optionalParams)
            // "assert", "clear", "count", "debug", "dir", "dirxml", "error", "group", "groupCollapsed", "groupEnd", "info", "log", "msIsIndependentlyComposed", "profile", "profileEnd", "time", "timeEnd", "trace", "warn"

            // Safari (2012. 07. 23.): https://developer.apple.com/library/safari/#documentation/AppleApplications/Conceptual/Safari_Developer_Guide/DebuggingYourWebsite/DebuggingYourWebsite.html#//apple_ref/doc/uid/TP40007874-CH8-SW20
            // assert(expression, message-object), count([title]), debug([message-object]), dir(object), dirxml(node), error(message-object), group(message-object), groupEnd(), info(message-object), log(message-object), profile([title]), profileEnd([title]), time(name), markTimeline("string"), trace(), warn(message-object)
            // "assert", "count", "debug", "dir", "dirxml", "error", "group", "groupEnd", "info", "log", "profile", "profileEnd", "time", "markTimeline", "trace", "warn"

            // Firefox (2013. 05. 20.): https://developer.mozilla.org/en-US/docs/Web/API/console
            // debug(obj1 [, obj2, ..., objN]), debug(msg [, subst1, ..., substN]), dir(object), error(obj1 [, obj2, ..., objN]), error(msg [, subst1, ..., substN]), group(), groupCollapsed(), groupEnd(), info(obj1 [, obj2, ..., objN]), info(msg [, subst1, ..., substN]), log(obj1 [, obj2, ..., objN]), log(msg [, subst1, ..., substN]), time(timerName), timeEnd(timerName), trace(), warn(obj1 [, obj2, ..., objN]), warn(msg [, subst1, ..., substN])
            // "debug", "dir", "error", "group", "groupCollapsed", "groupEnd", "info", "log", "time", "timeEnd", "trace", "warn"

            // Chrome (2013. 01. 25.): https://developers.google.com/chrome-developer-tools/docs/console-api
            // assert(expression, object), clear(), count(label), debug(object [, object, ...]), dir(object), dirxml(object), error(object [, object, ...]), group(object[, object, ...]), groupCollapsed(object[, object, ...]), groupEnd(), info(object [, object, ...]), log(object [, object, ...]), profile([label]), profileEnd(), time(label), timeEnd(label), timeStamp([label]), trace(), warn(object [, object, ...])
            // "assert", "clear", "count", "debug", "dir", "dirxml", "error", "group", "groupCollapsed", "groupEnd", "info", "log", "profile", "profileEnd", "time", "timeEnd", "timeStamp", "trace", "warn"
            // Chrome (2012. 10. 04.): https://developers.google.com/web-toolkit/speedtracer/logging-api
            // markTimeline(String)
            // "markTimeline"

            assert: noop, clear: noop, trace: noop, count: noop, timeStamp: noop, msIsIndependentlyComposed: noop,
            debug: log, info: log, log: log, warn: log, error: log,
            dir: log, dirxml: log, markTimeline: log,
            group: start('group'), groupCollapsed: start('groupCollapsed'), groupEnd: end('group'),
            profile: start('profile'), profileEnd: end('profile'),
            time: start('time'), timeEnd: end('time')
        };

        for (var method in methods) {
            if ( methods.hasOwnProperty(method) && !(method in console) ) { // define undefined methods as best-effort methods
                console[method] = methods[method];
            }
        }
    })();

2  

Noticed that OP is using Firebug with IE, so assume it's Firebug Lite. This is a funky situation as console gets defined in IE when the debugger window is opened, but what happens when Firebug is already running? Not sure, but perhaps the "firebugx.js" method might be a good way to test in this situation:

注意到OP正在使用IE的Firebug，所以假设它是Firebug Lite。当调试器窗口打开时，在IE中定义控制台，但是当Firebug已经运行时，会发生什么情况呢?不确定，但可能是“firebugx”。在这种情况下，js“方法可能是一个很好的测试方法:

source:

来源:

https://code.google.com/p/fbug/source/browse/branches/firebug1.2/lite/firebugx.js?r=187

https://code.google.com/p/fbug/source/browse/branches/firebug1.2/lite/firebugx.js?r=187

    if (!window.console || !console.firebug) {
        var names = [
            "log", "debug", "info", "warn", "error", "assert",
            "dir","dirxml","group","groupEnd","time","timeEnd",
            "count","trace","profile","profileEnd"
        ];
        window.cOnsole= {};
        for (var i = 0; i