Window.dump() | Web API

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此特征是非标准的，且不在标准轨道中。不要在面向 Web 的生产站点中使用它：它不适用于每个用户。实现之间可能存在大的不兼容性，且行为将来可能改变。

Window.dump() prints messages to the (native) console.

句法

window.dump(message);
dump(message);

参数

message is the string message to log.

注意事项

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 process was started with 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 使用 console.log() . Privileged code can also use Components.utils.reportError and nsIConsoleService to log messages to the Error Console / Browser Console .

dump() is also available to XPCOM components implemented in JavaScript, even though window is not the global object in components. It is also explicitly made available in sandboxes . However, this use of dump is not affected by the preference mentioned below -- it will always be shown. It is therefore advisable to either check this preference yourself or use a debugging preference of your own to make sure you don't send lots of debugging content to a user's console when they might not be interested in it at all. Note that dump output from XPCOM components goes to stderr ，而 dump called elsewhere will output to stdout .

在 Gecko dump() is disabled by default – it doesn't do anything but doesn't raise an error either. To see the dump output you have to enable it by setting the preference browser.dom.window.dump.enabled to true . You can set the preference in about:config 或在 user.js file . Note: this preference is not listed in about:config by default, you may need to create it (right-click the content area -> New -> Boolean).

On Windows, you will need a console to actually see anything. If you don't have one already, closing the application and re-opening it with the command line parameter -console should create the console or use -attach-console to use the existing console. On other operating systems, it's enough to launch the application from a terminal.

To redirect the console output to a file, run firefox without the -console option and use the syntax to redirect stderr and stdout to a file, i.e.:

firefox > console.txt 2>&1

If you would like the console messages to appear in the console you used to launch the application, you can use the Gecko Console Redirector . Precompiled binaries are available in the zipped archive https://github.com/matthewkastor/Redirector/archive/master.zip under Redirector-master\Gecko\Console Redirector\bin\Release Copy all the dll's and the exe to wherever you want. Then run Console Redirector.exe /?

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This is not part of any specification

元数据

最后修改： Feb 22, 2020

在此页

句法

参数

注意事项

规范

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