CODEWITHSUNDEEP
javascriptxmlgoogle-chrome-extensionfirefox-addonfirefox-addon-webextensions
Cornwell
Cornwell

Reputation: 3410

Inject javascript in XML file via content script

I know xml shouldn't really have javascript in it but I'm making a browser extension that needs to inject some code on every page to provide the user with some interesting statistics.

The problem is, I'm unable to get the injected code to run in XML documents as it looks like the script tag I create is treated as text?

The same code works fine in HTML

Here's what I have:

manifest.json:

"content_scripts": [
    {
      "matches": ["<all_urls>"],
        "all_frames": true,
        "match_about_blank": true,
        "run_at": "document_start",
        "js": ["scripts/content/countCalls.js"]
    }
  ]

countCalls.js:

let injectedCode = 'console.log("Hello from injected code");';
let script = document.createElement('script');
script.appendChild(document.createTextNode(injectedCode));

let parent = document.head || document.body || document.documentElement;
let firstChild = (parent.childNodes && (parent.childNodes.length > 0)) ? parent.childNodes[0] : null;
if (firstChild) {
  parent.insertBefore(script, firstChild);
} else {
  parent.appendChild(script);
}

test.xml:

<?xml version="1.0"?>
<main xmlns='http://www.w3.org/1999/xhtml'>
<script>
console.log("Hello from XML");
</script>
</main>

When I load test.xml in the browser I see this:

console.log("Hello from injected code");

and in the console I just see this:

Hello from XML

So the injected code is being treated like text. Anyway around this? Otherwise intentionally adding javascript to xml will cause it to bypass the extension

Upvotes: 2

Views: 2599

Answers (1)

woxxom
woxxom

Reputation: 73596

Simply create the script DOM element with an XML-compatible namespace:

let script = document.createElementNS('http://www.w3.org/1999/xhtml', 'script');

Upvotes: 2

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