vfs.file.contents item was used that reads the file with contents taken from here: big-list-of-naughty-strings

Result:

I cannot click anything..
After couple of minutes - it may start responding occasionally, but it it still very slow and still freezes anyway.
The size of the file is not that large - only ~740 lines.
On Chrome and Firefox - there are no issues. and they are not slowed in any way.

The cause could be in the "Script Injection" block of lines:

<script>alert(0)</script>
&lt;script&gt;alert(&#39;1&#39;);&lt;/script&gt;
<img src=x onerror=alert(2) />
<svg><script>123<1>alert(3)</script>
...
etc - other script injections..
...