A mobile web site project I've been working on has been recently been analyzed by a performance consulting firm and they came back recommending that we move all of our .css file links to the BOTTOM of the HTML to accommodate issues on the iPhone where .css files can block concurrent server requests.
I've always known this to be true on most browsers when it comes to .js files--hence the common practice of putting .js file links at the bottom of one's HTML--but I've never heard this about .css files.
I have yet to get a response from the consulting firm with cited references as to this being an actual issue on Mobile Safari. Has anyone else heard of this and, if so, know of any specific references that talk about it (perhaps from Apple directly?)
This is not intended to be an answer to your question, but as a reference:
Best Practices for Speeding Up Your Web Site from Yahoo:
Put Stylesheets at the Top
While researching performance at Yahoo!, we discovered that moving
stylesheets to the document HEAD makes pages appear to be loading
faster. This is because putting stylesheets in the HEAD allows the
page to render progressively.
Their recommendation to move CSS to the bottom is unusual - would appreciate it if you could share why they found this to be a good idea.
edit: Looking at the general guidelines on apple.com, I couldn't find any particular reference to CSS inclusion applicable only to Mobile Safari. The basic, general instructions still state that you should place CSS in the <head>. See this page.
If you load up the following URL (http://waynepan.com/s/con/) on your desktop and then your mobile browser you'll observe a curious behaviour; On a desktop browser (Chrome & Firefox at least) you'll see the boxes populating from top left to bottom right (in the same order as on the source code) and on a mobile device (iPhone, iPad at least) you'll see the exact opposite occurring.
Albeit undocumented, this observation would suggest that the mobile browser reads the main html file first and then proceeds to render the page bottom-to-top thus loading latter hrefs first and working it's way up to the top.
You'll also observe that on the desktop browser up to 6 boxes are populated concurrently and on the mobile browser up to 4 are populated - this accounts for the maximum concurrent connections that are allowed by the browser in question to any one host.
Therefore, if page load and render speed is especially important in your mobile web app, take special care to order the loading of elements accordingly. I think your consultancy firm colleagues had observed a similar behaviour and wanted to force the CSS to load before all the other content - it would all render with the correct styles from the outset, giving the illusion (or user experience) that the page loads faster.
Alas, my 1 cents worth - I hope it is food for thought. :-)
Related
Since google updated their way of scoring mobile I have trouble to optimise my websites.
I want to know what am I doing wrong and what should be done to existing sites to make the score higher. Its easy to get 95-100 on desktop but on same site on mobile will be 25...
Before someone says to follow suggestions by insights then I will say that I do and I managed to remove most of them - worst thing is that the score didn't move at all. This is the biggest struggle I have, it seems that whatever I do it wont be good enough...
I followed this guide https://kinsta.com/blog/google-pagespeed-insights/ + some of my own solutions.
Is there anyone that has any good tips or permanent solution for this issue?
Google Report
As evident from your Page Speed Insights report, the main factor responsible for your low score is images. The solution to this is using RESPONSIVE IMAGES, which will drastically improve the speed of your website on mobile. What it basically means is that, you'll have to keep different sizes of the same image available for the browser and browser will decide which version of the image is suited on a particular resolution.
1) Here's everything you need to know about Responsive Images --> Responsive Image (CSS Tricks)
2) You have to shift the <link href=".." .../> and <script> tags from top of the page to the bottom of the page, just after the <body> tag. This will fix the `Eliminate render blocking resources issue.
3) You can use Javascript Minifier to minify your JS. Just paste your existing JS code inside the Input Javascript box on the website and click MINIFY
Also, cache policy is also one of the factors, bringing your score down. An efficient Cache policy will make browsers, load your website faster, after the first load. Cache handling is server specific, its different for Apache, Express etc.
http://shapeandslim.com/
If we drag it through the chrome it show that it is responsive, also i have checked it in iphone5 safari, it works fine as well but when we try google mobile friendly test it just fails, only home page fails while rest of the pages successfully passed the mobile friendly test. Also the preview that it shows on google test page it seems like that the css is not being used. whats seems to be the problem here and how to solve it.
I had these same problems. I found that I had a robots.txt file that was prohibiting crawling of the folder that contained my bootstrap CSS files, so it wasn't rendering correctly for crawlers. I changed all of my fonts to ensure they are at least 16px. I also added the following to all of my images: class="img-responsive". I hope this helps!
From Google Webmaster FAQ
I have a great mobile site, but the Mobile-Friendly Test tells me that my pages aren't mobile-friendly. Why?
If a page is designed to work well on mobile devices, but it’s not passing the Mobile-Friendly Test, the most common reason is that Googlebot for smartphones is blocked from crawling resources, like CSS and JavaScript, that are critical for determining whether the page is legible and usable on a mobile device (i.e., whether it’s mobile-friendly). To remedy:
Check if the Mobile-Friendly Test shows blocked resources (often
accompanied with a partially rendered image).
Allow Googlebot to crawl the necessary files.
Double-check that your page passes the Mobile-Friendly Test.
Use Fetch as Google with Submit to Index and
submit your updated robots.txt to Google to expedite the
re-processing of the updated page (or just wait for Google to
naturally re-crawl and index).
Source https://googlewebmastercentral.blogspot.dk/2015/04/faqs-april-21st-mobile-friendly.html Question 6
The reasons according to Google as to why your site is not mobile friendly is because of the following:
Content wider than screen
Links too close together
Uses incompatible plugins
Another reason could be that:
This page may appear not mobile-friendly because the robots.txt file
may block Googlebot from loading some of the page's resources. Learn
how to unblock resources for Googlebot.
Google is Rendering your website as follows, I suggest checking the cache and CSS files accordingly. Make sure the view does now exceed the size of the screen
Check the link here for more insight on your page and how to fix it
my site seems to be downloading very slowly. I recently changed the CSS and HTML to improve the layout, but I think I might have messed it up somehow.
Can anyone give me feedback on things I could do to speed it up?
Thanks.
www.aerlawgroup.com
There are many online Web Optimization sites that you can use.
I've attached some optimized results for your page.
From http://www.webpagetest.org/
See The Result
and you can use Google Page Speed Link
Simply, I would suggest one thing based on your page design and the code is..., use CSS Simplify Tool and the HTML Symplify Tool. It reduces the Page Loading time dramatically. and as well as some Image Compression Tool too.
One thing that really reduces the page speed is Flash contents or Images. so be focus on that primarily
http://csslint.net/ for linting
http://csscomb.com/ for ordering attributes
http://prefixr.com/ for adding browser prefixes
There are many many factors that come in play with a slow page besides CSS/HTML. The size of the images, whether they are optimized, how fast the server delivers, caching, etc...
I would recommend using Google PageSpeed Insights or similar service - they show you a lot of info.
Go to https://developers.google.com/speed/pagespeed/insights/
Edit: Your URL loads this JS file which has an anonymous function that runs again and again:
http://s3.amazonaws.com/scripts.hellobar.com/bfa7653204b92054d559e0d8dd1ba2dd6fbdc183.js
You can view for yourself by using a web inspector - I am in Safari 7 and under Timelines on the Inspector panel - select "Layout & Rendering" from leftside menu and reload page. You can see that the HelloBar is doing some kind of adjusting over and over.
Currently, I'm investigating several tips/recommendations for improving the performance of web sites. So, I've started with Steve Souders' excellent books (High performance web sites and even faster web sites), but I've got a couple of questions regarding some of the rules that are presented. FOr instance, chapter 5 of High performance web sites say that CSS stylesheets should be put at the top of the page because putting them at the bottom stops the progressive rendering that is performed by the browsers. According to Steve, some browsers (most notably IE) do get stuck with it and show a blank page instead of showing the items progressively. Here's the url for that test page:
http://stevesouders.com/hpws/css-bottom.php
Now, I do understand that we're talking about a book with a couple of years and that browsers (including IE) have been updated and improved. The reason I'm asking this is because I can't reproduce the behavior he mentions with any current version of FF, Chrome or IE.
Well, the thing is that Yahoo (http://developer.yahoo.com/performance/rules.html#css_top) and google (https://developers.google.com/speed/docs/best-practices/rendering#PutCSSInHead) still say that.
So, what I'd like to know is if browsers have evolved in this area and this is only problematic for, say IE 8? If that is the case, why haven't yahoo and google updated their recommendations? (btw, I've tried simulating IE7 from within IE11 and still don't see the expected result that is described in the book...)
*UDPATE*One more final note: I've decided to reproduce Steve's cgi script in asp.net and I've created a simple generic handler that does the same thing as the sleep.cgi script. what I'm seeing here is that putting a stylesheet reference (which takes some time to load - I've went with 10 seconds) inside the head ends up producing the blank page problem that is reported in the book. If you put at the end, the browser ends up rendering everything and making a second pass for applying the styles after they have been loaded. In my opinion, this makes sense because when you put the style in the header element, the browser is holding up until it gets the styles before rendering (notice that the other referenced components are still being downloaded on the background, but they're not being shown in the screen). On the other hand, when they're at the bottom, the browser will simply apply the current styles until it gets stuck in the stylesheet. WHen that happens, it will only show the html it has loaded until the stylesheet (if there are any images below it, the browser will still download them but it will only render them after the styles have been loaded).
So, after these tests, I'm starting to think that 1.) I'm missing something here or 2.) yahoo and google recommendations are no longer valid today.
Thoughts?
Thanks guys!
Simply inserting a <link> tag in the footer is not the way to defer stylesheets. The currently accepted method is to attach it using javascript:
<script>
function loadStyleSheet(e){if(document.createStyleSheet)try{document.createStyleSheet(e)}catch(t){}else{var l;l=document.createElement("link"),l.rel="stylesheet",l.type="text/css",l.media="all",l.href=e,document.getElementsByTagName("head")[0].appendChild(l)}}loadStyleSheet("/your/stylesheet.css");
</script>
Optimizing your page for speed involves determining what CSS is above the fold, inlining that part in the header, and loading the main stylesheet later using the above method.
I recommend doing some searches for "above the fold css" and check out Google Pagespeed Insights.
https://developers.google.com/speed/pagespeed/insights/
I have a modified version of a flex calendar found Here, and though it looks alright on most computers I've seen, there is a problem on two of the three servers here. Because of the way Citrix is setup here, I need to have it functional on all of the servers.
When it loads, everything is stretched out vertically, and the numbers are missing on the date boxes. If you mouse-over the flex buttons, they jump to the right size, but there is still rendering errors.
The modifications I made had no effect, because the servers give the same results on both my version and the demo version hosted online. As far as I can tell, the servers are identical (IE version, Flash version, etc.)
How can I get it to display normally?
Initial View
After Mouseover
Usual Demo
Demo in bad server
Edit: On the server that renders it improperly, Firefox renders it fine, but Firefox cannot be used for other (unchangeable) reasons.
From the images it appears this is how the SWF appears in the Browser of each server - one good and one bad. Not how the SWF appears in any browser while being hosted from each server.
Sense it is the browser display that is not working correctly I would assume it is a rendering problem with the browser and not the server.
1.) The problem could come from JavaScript being disabled in one of the browsers and the view being taken from the embed tag. Check to ensure that it looks the same with JavaScript both on and off.
2.) The height being 100% could also be messing it up in the browser. Try setting the height to a specific value (800px) and see if that corrects the problem.
3.) Make sure that the browsers are the same. Is one IE 7 and one IE 8? If they are the same, check the version number to ensure that all updates are the same for each.
4.) View the site from another computer that is connected to the server.
Number 1 and 2 would be my best guess as a way to troubleshoot.