Windows 7, Internet Explorer 11.
On web pages that contain HTML source code lines longer than 160 characters, the long lines are unexpectedly being split into multiple lines of no more than 160 characters each. The split is performed by the insertion of an ASCII carriage return and line feed pair.
The splitting never occurs within a word. It occurs at white space or at certain non-alpha-numeric characters; e.g., at a "[".
If the split occurs within some embedded Javascript, the Javascript code is sometimes rendered un-executable.
The splitting is intermittent. Sometimes, the very same web page's source code is not split up, and the page's Javascript operates correctly.
When splitting does occur, all source lines longer than 160 characters are affected; not just those that contain Javascript.
I don't know whether the splitting is being performed by Internet Explorer, an Add-on, or by the web server itself.
Yes, I'm aware that SMS text messaging has a 160-character limit, but I suspect that is irrelevant here.