From time to time I receive a request about problems with javascript save process in content editor (rich text editor tinymce). To activate javascript in rich text editor it will be required to extend rich text editor and switch some options in shop's back office. An example of such request you can find below:

Dear Milosz, I've just installed TinyMCE Pro Module, since I needed to insert some js code into some CMS pages. The problem is that when I paste anything like: ... or also any inline script like: $( document ).ready(function() {console.log( "ready!" );}); it is deleted (first case) or replaced with: Overrides are active in Prestashop BO.
Thanks, best regards 

Activate javascript support in PrestaShop

to use javascripts in prestashop contents editor please go to preferences > general - there is an option named "html purifier". Disable it (it can't be active because it removes inline-javascripts or modifies the javascript code you want to use). Thanks to this you should be able to save the scripts properly. Screenshot for reference: 

Jquery as an inline script in PrestaShop 1.7 ?  

Regarding to the code you try to save, from what i see it is a jquery code:

$( document ).ready(function() {console.log( "ready!" );});

if you are on prestashop 1.7.x - you will need to replace the jquery code for $(document).ready(function(){}); code because prestashop in version 1.7 does not allow to run this code inline.

instead - to run jquery code after page is "ready" you should use code like this:

document.addEventListener("DOMContentLoaded", function(event) {
console.log( "ready!" );
// this is $(document).ready equivalent without jQuery
// you can use jquery code here
});