Javascript - error when a script tag in a string [duplicate]

Question

I have a page with the following code:

<script>
window.str = '<script></script>';
</script>

This results in an error:

Uncaught SyntaxError: Unexpected token ILLEGAL

What's going on? Entering the same code into the console runs without issue. Here is a jsbin demonstrating the issue

The </script> tag inside the string closes the first <script> tag, leaving you with invalid JavaScript. HTML doesn't know about JavaScript, it only sees the closing tag. It works in the console because the code is not in a HTML context. — Felix Kling
– Felix Kling, Commented Apr 13, 2014 at 3:09
Oh good find @FelixKling that was it. Wow, I don't think I've learned something new about javascript in months if not years. — George Mauer
– George Mauer, Commented Apr 13, 2014 at 3:10
:) It's more an HTML issue than a JS issue, I'd say, but it's nice to learn something new :) — Felix Kling
– Felix Kling, Commented Apr 13, 2014 at 3:11
Yeah, I'll leave it up and vote to close - I asked in a different way than the dupe OP. — George Mauer
– George Mauer, Commented Apr 13, 2014 at 3:13

pennstatephil · Accepted Answer · 2014-04-13 03:05:43Z

3

the error went away when I escaped the / with a \.

answered Apr 13, 2014 at 3:05

pennstatephil

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Comments

chaslewis · Accepted Answer · 2014-04-13 03:07:17Z

1

The hackish work-around for this is something like:

<script>
window.str = '<scr' + 'ipt></scri' + 'pt>';
</script>

In this way, you wind up with the string you want without confusing the parser.

Or, insert it as a DOM element if that is the ultimate goal.

answered Apr 13, 2014 at 3:07

chaslewis

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