Usage of external scripts doesn't block HTML parsing

Author: pmdartusCreated Nov 1, 2018Updated Sep 17, 2026

Labelsbugparsing

Basic info:

Node.js version: v8.11.4
jsdom version: v13.0.0

Minimal reproduction case

javascript

var { JSDOM } = require("jsdom");

new JSDOM(`
<!DOCTYPE html>
<meta charset=utf-8>
<script>
    console.log("sync 0:", document.querySelectorAll('p').length);
</script>

<!-- Some external script -->
<script src="https://unpkg.com/[email protected]/dist/jquery.js"></script>

<p>First</p>
<script>
    console.log("sync 1:", document.querySelectorAll('p').length);
</script>

<p>Second</p>
<script>
    console.log("sync 2:", document.querySelectorAll('p').length);
</script>
`, {
    resources: "usable",
    runScripts: "dangerously"
});

The usage of external script doesn't block jsdom from parsing the rest of the page.

Actual output:

sync 0: 0
sync 1: 2
sync 2: 2

Expected output:

sync 0: 0
sync 1: 1
sync 2: 2

How does similar code behave in browsers?

https://jsfiddle.net/pmdartus/06sed5nt/

Source: jsdom/jsdom

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