What do you mean freezes? Also post your error logs. Have you tried changing the file permissions writable to the web server?

What i meant by freezes is that the drop down functions for the back-end menu and similar functions on the whole site does not work and instead, when i click on it, it just reloads the page or the url and nothing happens. I check the error log and their was nothing.

Try flushing the cashes. And see what issues you see in the browser console.

I checked the file permissions for when the server PHP VERSION is switched to PHP 5.5+ and they are correctly set the same way as the permissions for the server running on PHP 5.4.8. I check the site on PHP 5.4.0 and PHP 5.4.13 and it works correctly but as soon as i switched the PHP VERSION to 5.5.0 and 5.5.13, that is when i have this issue with the JS and some CSS views. I have tried with all plugins deactivated, including the Elgg 1.12.5 bundled plugins deactivated  and i still have same issue. Everything works perfect on my Desktop XAMPP SERVER. I feel this issue might be coming from the ONLINE HOSTING SERVER environment, so i ask to be migrated to a new server environment with probably same PHP version configuration as my desktop XAMPP SERVER of PHP 5.6.11 and hope it works. In the mean time, am still waiting for feedback from their tech guys.

Yeah what Ismayil said, open the console in your browser, flush the cache and see what error messages shows up. I have that happened to me before and it was due to an Nginx config file.

I found this in the Mozilla Browser Console logging:

Asynchronous operation was aborted as selection changed. breadcrumbs.js:129
DOMException [InvalidAccessError: "A parameter or an operation is not supported by the underlying object"
code: 15
nsresult: 0x8053000f
location: resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/styleinspector/css-logic.js:1335] protocol.js:907
Protocol error (unknownError): InvalidAccessError: A parameter or an operation is not supported by the underlying object rule-view.js:54
Protocol error (unknownError): InvalidAccessError: A parameter or an operation is not supported by the underlying object Promise-backend.js:937
Asynchronous operation was aborted as selection changed. breadcrumbs.js:129
DOMException [InvalidAccessError: "A parameter or an operation is not supported by the underlying object"
code: 15
nsresult: 0x8053000f
location: resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/styleinspector/css-logic.js:1335] protocol.js:907
Protocol error (unknownError): InvalidAccessError: A parameter or an operation is not supported by the underlying object rule-view.js:54
Protocol error (unknownError): InvalidAccessError: A parameter or an operation is not supported by the underlying object Promise-backend.js:937
Protocol error (noSuchActor): No such actor for ID: server1.conn2.profilerActor20 Promise-backend.js:937
ready viewticket.php:23:3

What does your php error log say?

php error log is empty

I'm gonna assume you're running on Apache so check if your www or public_html directory has a writeable permission by www-data. You also need to change the permission recursively.

Does this mean everything working fine in other browsers, and issues only show themselves in Firefox? Reading up on the error you have posted, it seems your code is trying to make a cross-origin request - are you loading something via AJAX from another server?