How to Combine external JavaScript

you seem to be using W3 Total Cache’s minify, not Autoptimize Alex? Disable all minify features in W3TC and make sure AO is active (view source and you should see autoptimize in your HTML)

frank

Hello. Thank you for your reply. I have done that, but the warning still shows up on Pingdom and the website loading speed is still very slow. I even enabled Jetpack’s CDN, but to no avail.

ah, you have revolution slider; that uses JS to load other JS-files and as such AO doesn’t “see” those extra JS-files, leaving them un-optimized.

regarding loading speed; one of the perfomance killers is https://hsa.hr/?custom-css=1f6f342b02, try moving the CSS there to WordPress core’s “additional CSS” in the customizer. 2nd performance issue is an admin-ajax.php call that takes 3s to load, try identifying the plugin that does that and zap it ??

Hello. So I should kill revolution slider, that custom CSS and the specified ajax or something plugin? How can I find out which plugin is admin-ajax.php?

How can I move the CSS specified? https://hsa.hr/?custom-css=1f6f342b02

getting rid of revolution slider would help performance, yes.

regarding admin-ajax.php; you’d have to either use the browser developer console to look at the POST request parameters or you could disable/ enable your plugins one by one until you don’t see the long admin-ajax.php call any more?

regarding the CSS; same thing (enabling/ disabling plugins and/ or briefly switching themes).

Hello. I have done all of that, disabled rev slider and admin-ajax.php. I deleted all of the custom CSS I added, but the site still loads slowly. Can you take a look at it please and check what else is slowing the site down?

Thank you very much.

4.7s load time, see https://www.webpagetest.org/result/180822_GH_88d7ac60702a933a869f6b2264538c49/ so not too bad actually.

you should be able to improve on image weight somewhat (esp. /wp-content/uploads/2018/07/blackboard-business-chalkboard-355988.jpg is way to big).

as you can see in the waterfall chart you’re loading a lot of google fonts, try trimming down on that.

How can I kill all of the google fonts?

depends on how they are loaded, but you could start by trying out the Google Font options on AO’s Extra tab?

I have it turned on but obviously it’s not working as supposed. How do I fix it?

In that case you’ll have to try to identify the plugin(s) that are adding those, check those plugins for options to turn google fonts of and if that option isn’t there, ask the developers of those plugins for help?