我使用Firebug,并有一些语句像:
console.log("...");
在我的页面上。在IE8(可能是更早的版本),我得到脚本错误说“控制台”是未定义的。我试着把这个放在我页面的顶部:
<script type="text/javascript">
if (!console) console = {log: function() {}};
</script>
我还是会得到错误。有办法消除错误吗?
我使用Firebug,并有一些语句像:
console.log("...");
在我的页面上。在IE8(可能是更早的版本),我得到脚本错误说“控制台”是未定义的。我试着把这个放在我页面的顶部:
<script type="text/javascript">
if (!console) console = {log: function() {}};
</script>
我还是会得到错误。有办法消除错误吗?
当前回答
为了更健壮的解决方案,使用下面的代码(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;
}
}
}());
其他回答
我使用的是fauxconsole;我修改了css一点,使它看起来更好,但工作得很好。
根据之前的两个答案
维尼修斯·莫赖斯 曾国藩
和文件
Internet Explorer (ie10) Safari(2012。07. 23)。 Firefox(2013。05. 20)。 Chrome(2013。01. 25.)和Chrome(2012。10. 04)。 还有我的一些知识
下面是针对该问题的最佳实现,这意味着如果有一个真正存在的console.log,它将通过console.log填补不存在方法的空白。
例如,对于IE6/7,你可以用alert代替日志记录(愚蠢但有效),然后包括下面的怪物(我称之为console.js): [请随意删除你认为合适的评论,我把它们留作参考,最小化可以解决它们]:
<!--[if lte IE 7]>
<SCRIPT LANGUAGE="javascript">
(window.console = window.console || {}).log = function() { return window.alert.apply(window, arguments); };
</SCRIPT>
<![endif]-->
<script type="text/javascript" src="console.js"></script>
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];
}
}
})();
console = console || {
debug: function(){},
log: function(){}
...
}
在IE9的子窗口中运行console.log时遇到类似问题,由window创建。打开功能。
在这种情况下,控制台似乎只在父窗口中定义,在刷新子窗口之前没有定义。同样适用于子窗口的子窗口。
我处理这个问题通过包装log在下一个函数(下面是模块的片段)
getConsole: function()
{
if (typeof console !== 'undefined') return console;
var searchDepthMax = 5,
searchDepth = 0,
context = window.opener;
while (!!context && searchDepth < searchDepthMax)
{
if (typeof context.console !== 'undefined') return context.console;
context = context.opener;
searchDepth++;
}
return null;
},
log: function(message){
var _console = this.getConsole();
if (!!_console) _console.log(message);
}
You can use the below to give an extra degree of insurance that you've got all bases covered. Using typeof first will avoid any undefined errors. Using === will also ensure that the name of the type is actually the string "undefined". Finally, you'll want to add a parameter to the function signature (I chose logMsg arbitrarily) to ensure consistency, since you do pass whatever you want printed to the console to the log function. This also keep you intellisense accurate and avoids any warnings/errors in your JS aware IDE.
if(!window.console || typeof console === "undefined") {
var console = { log: function (logMsg) { } };
}