问题
What's a surefire way of detecting whether a user has Firebug enabled?
回答1:
Original answer:
Check for the console object (created only with Firebug), like such:
if (window.console && window.console.firebug) {
  //Firebug is enabled
}
Update (January 2012):
The Firebug developers have decided to remove window.console.firebug. You can still detect the presence of Firebug by duck typing like
if (window.console && (window.console.firebug || window.console.exception)) {
  //Firebug is enabled
}
or various other approaches like
if (document.getUserData('firebug-Token')) ...
if (console.log.toString().indexOf('apply') != -1) ...
if (typeof console.assert(1) == 'string') ...
but in general, there should be no need to actually do so.
回答2:
If firebug is enabled, window.console will not be undefined. console.firebug will return the version number.
回答3:
As of Firebug version 1.9.0, console.firebug is no longer defined because of privacy concerns; see release notes, bug report. This breaks the above mentioned methods. Indeed, it changes the answer to Allan's question to "there is no way"; if there is another way, it's considered a bug.
The solution instead is to check for the availability of console.log or whatever it is you want to use or replace.
Here is a suggestion for a replacement for the kind of code that David Brockman is presenting above, but one that doesn't remove any existing functions.
(function () {
    var names = ['log', 'debug', 'info', 'warn', 'error', 'assert', 'dir', 'dirxml', 
                'group', 'groupEnd', 'time', 'timeEnd', 'count', 'trace', 'profile', 'profileEnd'];
    if (window.console) {
        for (var i = 0; i < names.length; i++) {
            if (!window.console[names[i]]) {
                window.console[names[i]] = function() {};
            }
        }
    } else {
        window.console = {};
        for (var i = 0; i < names.length; i++) {
            window.console[names[i]] = function() {};
        }
    }
})();
回答4:
It may be impossible to detect.
Firebug has multiple tabs, which may be disabled separately, and, are now not enabled by default.
GMail as it is can only tell whether or not I have the "console" tab enabled. Probing further than this would likely require security circumvention, and you don't want to go there.
回答5:
You can use something like this to prevent firebug calls in your code from causing errors if it's not installed.
if (!window.console || !console.firebug) {
    (function (m, i) {
        window.console = {};
        while (i--) {
            window.console[m[i]] = function () {};
        }
    })('log debug info warn error assert dir dirxml trace group groupEnd time timeEnd profile profileEnd count'.split(' '), 16);
}
回答6:
Keep in mind in Chrome window.console also returns true or [Object console].
Furthermore, I would check whether Firebug is installed with
if (window.console.firebug !== undefined) // firebug is installed
Below is what I get in Safari and Chrome, no firebug installed.
if (window.console.firebug) // true
if (window.console.firebug == null) // true
if (window.console.firebug === null) // false
The Is-True and Is-Not Operators obviously do type coercion, which should be avoided in JavaScript.
回答7:
Currently, the window.console.firebug has been removed by latest firebug version. because firebug is an extension based JavaScript debugger, Which defined some new function or object in window.console. So most times, you can only use this new defined functions to detection the running status of firebug.
such as
if(console.assert(1) === '_firebugIgnore') alert("firebug is running!"); 
if((console.log+'''').indexOf('return Function.apply.call(x.log, x, arguments);') !== -1)  alert("firebug is running!");
You may test these approach in each firebug.
Best wishes!
来源:https://stackoverflow.com/questions/398111/javascript-that-detects-firebug