Prevent WordPress from adding linebreaks to javascript embedded in a page

On a page in WordPress, If I enter the following code:

var r="<li><a href="#"><img src="" + slide.src + '" width="50" height="50" /></a></li>';

it is rendered in the browser as

  var r="
<li><a href="#"><img src="" + slide.src + '" width="50" height="50" /></a></li>

';

and it gives me this error in FF Console SyntaxError: unterminated string literal var r="

This is a single-user blog, so I am “Administrator”.

How do I prevent WordPress from fouling my code?

In the new WordPress (WP 5+) Editor – Gutenberg, you can use a “Custom HTML” block to prevent the automatic line breaks and paragraphs:

on Visual Editor click + > Formatting > Custom HTML – and put your JavaScript in there

on Code Editor enclose your JavaScript with <!-- wp:html --> <!-- /wp:html -->