GM_log

Description

This API method allows script authors simple access to logging informational messages in the Error Console via a chrome message.

If no messages are visible, make sure you navigate to about:config?filter=javascript.options.showInConsole and about:config?filter=javascript.options.strict change the values to true. This can be helpful for debugging.

⬆ ⬇ | Examples | GM_log and Firebug | See Also | Notes

Syntax

GM_log( message )

Value: Function
Returns: undefined
Compatibility: Greasemonkey 0.3b - 3.12.0
Access: @grant

Parameters

Properties
message

• All properties are optional except message.

⬆ ⬇

Properties

---

message

Value: String, Integer or Boolean
Usage: message = "ARGHHH!";

• Message to send to the JavaScript error console.
• While the value may be a non-string, it will convert the argument to a string. There may also be some instances of visual clipping on large numerical values during conversion. This is a feature present in Mozilla based JavaScript console logging.

⬆ ⬇ ⇧

Examples

⬆ ⬇

Core

GM_log("Hello, World!");

or

GM_log("Warning, " + someInputField.value + "!");

⬆ ⬇ ⇧

GM_log and Firebug

Since Firebug 1.0, extensions.firebug.showChromeMessages must be set to true for GM_log messages to show up in the Firebug console. It is also recommended to enable extensions.firebug.showChromeErrors, as doing so will reveal syntax errors and script breaks.

This can be done from about:config, or from the Firebug GUI. Go to the "Console" tab, then click the arrow next to the tab's name, and ensure that "Show Chrome Errors" and "Show Chrome Messages" are checked.

However, one should note that since GM_log converts any passed parameter to a string and resides in the chrome scheme. If Firebug is present on all systems it could be more advisable to simply use console.log, which will allow Firebug’s DOM Inspector on the logged objects. On sites with a large amount of warnings or errors this may cause the browser to hang.

⬆ ⬇

See Also

⬆ ⬇

Notes

⬆