Optimize CSS Delivery
-
Hi,
I am loading 3 CSS files here: http://www.viatrading.com/wholesale/9/Domestics.html
PageSpeed is telling me I "should fix" the delivery of these CSS Files (see image).
I read https://developers.google.com/speed/docs/insights/OptimizeCSSDelivery , but can't figure out which is my case. The CSS are big, but even if I split them in several, all CSS files are still showing up as render-blocking. I moved them to the header/footer, but the message is still appearing.
Do you know what might be the problem and how to solve it?
Thank you,
-
The concept that Google is trying to setup here is that your CSS and JS contain elements that are critical for the page to render. The problem is that as the browser downloads them, they can block other resources from being downloaded. This is because the browser wants to read these files to see everything they need to download to render the page. Part of fixing render blocking is to reduce the number of files that a browser has to download, especially those in the critical path (html, CSS, JS) that can block the downloading of other files (images, etc)
Google is getting even more specific in your case. They are looking at the "above the fold" parts of your page. What Google wants you to do is take any CSS or JS that you use to render what is "above the fold" on that page and inline that code into your HTML file. That way when the browser downloads the HTML file it has all it needs to render the visible / "above the fold" part of the page vs having to wait for the CSS and/or JS files to download.
The problem is that defining "above the fold" is relative due to the multiple browser size and OS and devices that your web server sees on a regular basis.
If you have a really good front end developer, they can take the time to figure out what viewport size is the most common and then take all the CSS and JS and inline that (and note this may be different depending on the page) into your HTML (and this assumes that your CSS and JS do not bloat your HTML file size too much). One approach is to take your most common large viewport size and then inline all those items into your HTML that are above the fold so you have everything covered as the viewport gets smaller. The issue there (and this is also with most responsive sites) is that you have a lot of code bloat for your phone browsers. You can also use a sniffer to determine what the size of the viewport is and then having the appropriate amount of CS and JS inlined on the fly. I have also seen people suggesting that we should design websites for the phone first and then expand out from there.
This is the best website I have seen that talks about how all these files interact and what Google is really getting at
https://varvy.com/pagespeed/critical-render-path.html
Here is what I would do.
- Have a single CSS file for your site and host it on your server, not an external domain. This is best practice. Take the time to strip out all of the stuff you do not use out of the CSS to get the file size down. Minify and compress it, reference your CSS in your header. This may help with the render blocking as you are reducing the number of files requested to just 1, but it may not help with the above the fold render blocking.
If you want to move forward with with "fixing" the above the fold render blocking. Extract the CSS that is critical to render above the fold items on your site (noting the caveats above) and place it inline within your HTML file and then put the rest in your single CSS file. https://varvy.com/pagespeed/optimize-css-delivery.html
- Have a single JS file and host it on your server. If there is any external JS try and see if you can host it within your single JS file. Strip out all the JS you do not use to get the file size down. Minify and compress it.
If you want to get past the render blocking above the fold item above, figure out what JS is needed to render the page above the fold. Inline that JS within your HTML and then setup a single file for all the other JS and then defer loading of that file using this technique: https://varvy.com/pagespeed/defer-loading-javascript.html
I noticed your external JS file to Googleadservices. You may not be able to put that JS into your main JS file and have to keep the external JS reference. I would then try and defer the loading of that using the technique above. You need to do some testing to make sure that doing this does not throw off how your ads are displayed or tracked. I would also make sure your GA or other web tracking JS code is inlined as well, otherwise you risk throwing off your web stats.
This is what makes all of this tricky. The Google page speed tool is just looking at a list of best practices and seeing if they are present or not. They are not looking to see if your page is actually getting faster or not, or if you change any of these things if they throw off the function of your site.
https://developers.google.com/speed/pagespeed/insights/
PageSpeed Insights analyzes the content of a web page, then generates suggestions to make that page faster
This is why with all of this you need to use a tool that shows actual page speed and will show a waterfall chart with timings to see how everything interacts. webpagetest.org is a common one.
It gets really complicated, really fast, and this is where a a really good front end guy or gal is worth it to look at these things. I would start with my initial simple suggestions above and not sweat the above the fold stuff. Test your site with actual speed and see how it does. You can also setup GA to give you page speed data. You can then decide if you need to take it to the next level.
Another thing you can try (I have not been able to get this to work for me) is that Google has a tool that can do all the "above the fold" inlining and other speed tricks for you
https://developers.google.com/speed/pagespeed/module/
Just like above, I would benchmark your performance and then see if this makes a difference on your site.
Good luck!
-
The main thing this is trying to communicate is that your CSS files should come above / before any Javascript files. When the browser downloads your HTML, it starts at the top and goes down and downloads resources (CSS, JS, fonts, images, etc).
When the browser comes to a JS file, it calls the server to retreive the file, and once it's downloaded, the browser begins to execute that javascript. When that JS is executing, it's delaying the handling of CSS files which help paint the elements and make them look how you want.
Move your CSS files to be above all your JS files and see if that fixes it.
In general, most (not always ALL) JS files should be loaded as the last thing so that it doesn't block / delay the browser in rendering the page.
Got a burning SEO question?
Subscribe to Moz Pro to gain full access to Q&A, answer questions, and ask your own.
Browse Questions
Explore more categories
-
Moz Tools
Chat with the community about the Moz tools.
-
SEO Tactics
Discuss the SEO process with fellow marketers
-
Community
Discuss industry events, jobs, and news!
-
Digital Marketing
Chat about tactics outside of SEO
-
Research & Trends
Dive into research and trends in the search industry.
-
Support
Connect on product support and feature requests.
Related Questions
-
Optimizing images and more for page speed
Hey everyone! I run a comparison/affiliate site for men's clothing. On the side of that, I have a Squarespace site for inspiration, articles and outfit pictures. I've tried to optimize site speed for the Squarespace site without much success. I've run all pictures trough JPEGmini to decrease file size but it doesn't seem to be enough. Below I attached the result I got when I run one of the pages trough Lighthouse and GTmetrix. Do you have recommendations of what I can do to improve the results? Is it a good idea to use next-gen formats for pictures as Google suggests as an example? Kind regards,
On-Page Optimization | | JonastriesSEO
Jonas XU131T0.png sPD3w13.png1 -
How to optimize WordPress Pages with Duplicate Page Content?
I found the non WWW ans WWW duplicate pages URL only, more than thousand pages.
On-Page Optimization | | eigital0 -
Where would I start with optimizing my site
I am new here and am would love some constructive community feedback about a website I am working on:
On-Page Optimization | | paddyaran
Things like tags, serps, content, loading time, design, functionality, and anything that will improve.... The site is www.aranislands.ie Thanks!!0 -
On-Site Optimization Issue!
Hello, I have some confusion about how to structure my site to better in on-site optimization. I am using WordPress. Therefore, there are many things that I need to consider as following: Static Page for homepage OR Latest posts? Archive, Category, Author, Attachment and Tag pages - To put meta robots (no index, follow) or not to prevent duplication? If I use Static Page for homepage, do I need to add meta robots (no index, follow) to POINT 2 above or not? If I use Latest Posts for homepage, do I need to add meta robots (no index, follow) to POINT 2 above or not? To have breadcrumb or not? To have recent posts, comment, tag clouds or popular posts/comments widget or not? To have social sharing icons and related posts in single post or not? If you don't mind adding more tips that I don't know it would be very great! Thanks!
On-Page Optimization | | dinabrokoth0 -
How quickly should I change/edit sites to avoid potential over optimization penalty?
Regard today's White Board, I'm wondering how quickly one should start changing title tags, page content, footer links, etc. on sites? I operate a few different sites and some of them definitely have things that need to be changed. Would it be weird or trigger something in Google if all the sites were changed in 24 - 48 hours? Thanks for your help!
On-Page Optimization | | jdrrocks0 -
Optimally, how many times should the key word or phrase you are targeting for a particular page be mentioned or appear on that page?
Our marketing team is debating how many times the key phrase on each of our web store's product pages should include the word/phrase we are trying to be competitive with. Can you advise?
On-Page Optimization | | Glynlyon0 -
How long would it take for On-Page Optimization to have an effect on Google Rankings?
Hi there, I have a page on our website with an Interview with the author Tess Gerritsen. There has been a reasonable amount of Social Media buzz related to the page and lots of links. According to SEOMoz we are an A grade for the keyword Tess Gerritsen, we currently rank 29th on Google.co.uk for a 'tess gerritsen' search. My question is - how long would it take for any new changes to have an effect? I presume the answer would be whenever the page is crawled again. But is it wise to change one thing, then get crawled and see what the effect is, then the next day change something else and see what the effect is. Or is it wise to change one thing and then leave it a week or so to see the full effect of the change? Apologies for the vague question, if you need any more clarification just let me know. Thanks. Benj
On-Page Optimization | | Benj250 -
One domain with keyword optimized pages or multiple domains
Hi There. I have a client in the real estate law services business. Which is better for long term search traffic? 1. A single domain ie. smith and smith law.com with pages focussing on each neighbourhood they operate in ie. .com/real estate law manhattan.php, .com/real estate law brooklyn.php etc or 2. multiple domains each focusing on one neighbourhood the business operates in ie: real estate law manhattan.com, real estate law brooklyn.com etc Thanks for the help, Josh
On-Page Optimization | | dreadmichael0