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I want to make a simple extension, which is passing a variable from background to popup. The problem is, I get 'undefined' response.
Manifest:
{
"name": "Get var",
"description": "get var",
"version": "2.0",
"permissions": [
"activeTab"
],
"background": {
"scripts": ["background.js"],
"persistent": true
},
"browser_action": {
"default_title": "Get that variable",
"default_popup": "popup.html"
},
"manifest_version": 2
}
background.js
var myURL = 'aaa';
popup.html
<!doctype html>
<html>
<head>
<script src="popup.js"></script>
</head>
<body>
</body>
</html>
popup.js
document.addEventListener('DOMContentLoaded', function () {
var bg = chrome.extension.getBackgroundPage();
var myURL = bg.myURL;
alert(myURL)
});
551
Your code (exactly as you posted it in your question) is correct and should work fine. (In fact when I created a sample extension using the code you provided, it did work as expected.)
You either accidentaly changed something when copying-pasting the actual code or there is something else messing things up (something you left out of your post).
BTW, I would suggest looking into event-pages (i.e. non-persistent background-pages) which are more resource-friendly. Keep in mind, that moving to an event-page would require some changes in order for the code to work:
document.addEventListener('DOMContentLoaded', function () {
chrome.runtime.getBackgroundPage(function (bg) {
var myUrl = bg.myUrl;
alert(myUrl);
});
});
Note: I do not in any way imply that the reason you receive undefined is that you use a persistent background-page. The code you posted should work fine with a persistent background-page - it is just better practice to use an event page (whenever possible).
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