"Script Error." errors in window.onerror in Safari only

Question

I'm getting "Script Error." when catching errors in window.onerror, even with properly (I think) configured CORS headers on S3.

CORS config:

<?xml version="1.0" encoding="UTF-8"?>
<CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
<CORSRule>
    <AllowedOrigin>*</AllowedOrigin>
    <AllowedMethod>GET</AllowedMethod>
    <AllowedMethod>POST</AllowedMethod>
    <AllowedMethod>PUT</AllowedMethod>
    <AllowedMethod>HEAD</AllowedMethod>
    <MaxAgeSeconds>3000</MaxAgeSeconds>
    <AllowedHeader>*</AllowedHeader>
</CORSRule>
</CORSConfiguration>

HTML:

<script crossorigin src="https://s3.amazonaws.com/safari-script-error/foo.js" />

which contains:

window.addEventListener("keydown", function(event) {
  if (event.keyCode === 69) { // "e" button
    throw new Error("Oh shoot");
  }
});

JS:

window.onerror = function(event) {
  console.log(event);
}

Codepen: https://codepen.io/astashov/pen/yoEvRB

It works fine in Chrome, Firefox and IE11, and only shows "Script error." in Safari (I have Version 10.0.3 (12602.4.8)).

How to make it work in Safari too?

Answer 1

How to make it work in Safari too?

You can’t. Current Safari versions don’t support giving error messages to the onerror callback in the cross-origin case—even if a crossorigin attribute is specified on the script element.

Safari did support it previously, but subsequently regressed at some point.

There’s an open bug for this at https://bugs.webkit.org/show_bug.cgi?id=132945