There is a page http://example.com/1.php that includes javascript file as usual:
<script type="text/javascript" src="/util.js?1354729400"></script>
This file contain function named exampleFunction which I need to use in my userscript. Also I have an user script:
// ==UserScript==
// @name SomeName
// @namespace http://example.com/userscripts
// @description Greets the world
// @include http://example.com/*
// ==/UserScript==
window.onload = function () {
console.log(exampleFunction);
alert("LOADED!");
}
which works perfectly in Firefox and returns an error in Chrome:
Uncaught ReferenceError: exampleFunction is not defined
How do I make it work?
The reason that exampleFunction
was undefined is because Chrome userscripts operate in a sandbox ("isolated world"). Note that Greasemonkey scripts often operate in a sandbox too, but yours is currently running with an implicit @grant none
.
If your script were to use a GM_
function, it would stop working in Firefox too.
To make this script work on both browsers (and a few others, as well), use Script Injection similar to this answer.
However, there is another hitch, since that script is using window.onload
. Chrome userscripts, with the default execution start-mode, will often never see the onload
event.
To get around that, add // @run-at document-end
to the metadata block.
So the script becomes:
// ==UserScript==
// @name SomeName
// @namespace http://example.com/userscripts
// @description Greets the world
// @include http://example.com/*
// @run-at document-end
// @grant none
// ==/UserScript==
function GM_main () {
window.onload = function () {
console.log(exampleFunction);
alert("LOADED!");
}
}
addJS_Node (null, null, GM_main);
//-- This is a standard-ish utility function:
function addJS_Node (text, s_URL, funcToRun, runOnLoad) {
var D = document;
var scriptNode = D.createElement ('script');
if (runOnLoad) {
scriptNode.addEventListener ("load", runOnLoad, false);
}
scriptNode.type = "text/javascript";
if (text) scriptNode.textContent = text;
if (s_URL) scriptNode.src = s_URL;
if (funcToRun) scriptNode.textContent = '(' + funcToRun.toString() + ')()';
var targ = D.getElementsByTagName ('head')[0] || D.body || D.documentElement;
targ.appendChild (scriptNode);
}
If you want the equivalent to onLoad
, which doesn't fire till all images on the page are loaded, you want to use // @run-at document-idle
in your metadata block. The default, document-end, fires when the DOM is loaded, the equivalent of document.ready.
Have you tried calling examplefunction with brackets ? :) Like this:
console.log(exampleFunction());
If you try it in chrome console, you have to add brackets to call function.
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