未定义Javascript Dump（）

Question

Was just looking around MDN about window.location and the example that they had given was:

 dump(document.location); // Prints a string like // "http://www.example.com/juicybits.html" to the console 

So I open up my console and type in dump(document.location) and all I keep getting is dump is not defined . I even tried window.dump(document.location) .

I then proceeded to look at the API for dump on MDN here but it seemed like I was using it properly.

I also tried it in Firefox - but still kept getting undefined So I then tried enabling it with window.dump.enabled - but that didn't do anything for me either.

Here is a screen cap of my Mozilla console:

What could I be missing here?

Answer 1

这是特定于Firefox（mozilla）的功能。

Answer 2

It says right in the docs you link to (emphasis mine):

A common use of dump() is to debug JavaScript. The message passed to dump() is sent to the System Console (Native Console) if the Firefox proces was started withe the -console option . If the -console option was not specified then the output goes to stderr. Output from dump() is not sent to the Browser Console. Output can be sent to the Browser Console using console.log() . Privileged code can also use Components.utils.reportError and nsIConsoleService to log messages to the Error Console/Browser Console.

You can't enable it and have it do something other than what it says it'll do, you need to look in the correct place for output, which isn't the browser console, rather where the docs say.

You can call it from the console, and are . It returns undefined , just like console.log .

Type in dump :

[16:40:57.545] dump
[16:40:57.547] [object Function]

It's defined.