I'm having an issue with slow AJAX calls. This is a common question, but I've done everything suggested in all the research I can find. I'm hoping to get a consensus form people who read this.
Basically, I make an ajax request to a php page, which gets info from a database.
Here is the page.
I've timed all of my javascript, mySQL, and php scripts, requests, and pages.
(If you run firebug you can see my time markers in the console, as well as in the xml)
As an example -
The mysql request takes 20ms
The PHP page takes 50ms
The ajax success script, which processes the small amount of xml (less than 1k) and generates the markers, takes 8ms to run.
Yet, loading the page takes nearly 4 seconds.
So, assuming none of my scripts are lagging, this has to be a problem with the response time from the server, or my own internet connection, right?
I'd appreciate any theories or thoughts.
Thank you
Ok looked at your page and here are some of the issues I saw that would affect speed:
It takes 4ms to get your data in your getMarkers function but it takes 892ms to read the xml file. I would recommend falling back to vanilla javascript to read your xml file as the amount of find's you are performing is really harming your performance here.
Minify and combine all of the scripts that are local on your server. I was getting some really high response times. You can eliminate 4 http requests by doing this which with the response times on your server will help a bit. (Note don't combine jquery or jquery ui in this)
Since your server is a bit slow (not your fault this will vary as you are probably on shared hosting) I would recommend linking jquery and jquery ui to the google cdn hosted versions. Here is a post on that Jquery CDN
You have 24 images on your page; 23 of which are under 4KB. Combine those 23 into one CSS sprite image and assign a 1px X 1px blank gif to be the inline html image and use the CSS sprite image instead. Here is good article on what this is if you are unfamiliar: CSS Sprites explained also here is good online css sprites generator: CSS Sprite generator
Make sure you need Jquery UI for this page. I didn't see anything that would have required it. If you can remove it you save yourself 206k. Remember to remove the associated CSS file if it isn't needed. This would save you another 2 calls.
Didn't dig too deep but if you are not already kick off the call to setup the google map in a $(document).ready() that way the rest of your page can load and you can display a loading animation in that area. This way users know something is happening and your page will appear to load a lot quicker.
So you can greatly speed things up by doing the above. You would go from 82 components down to 51 local and 2 more on Google CDN. If you can improve that xml read time you can shave nearly another second off load time as well
Related
I try to improve the overall performance of loading time (especially images) with the Google Chrome Lighthouse extension of this website: https://muckenthaler.de/
When the Performance Test is finished I get a list of opportunities, please see this screenshot or test for yourself: https://capture.dropbox.com/YV5ii1vrj0xpfWwK
Under Serve images in next-gen formats are listed some image urls (like this one: https://muckenthaler.de/media/image/54/7c/cb/Sliderbild_Produkte_Steh_SItz_Tische_2.jpg) that don't even appear on the specific page but somehow seem to get loaded into it and affect the performance.
How could I prevent this and why are these image resources loaded?
Here are the WebPageTest results for this page: https://www.webpagetest.org/result/220529_AiDcZP_759/1/details/#waterfall_view_step1
All you need to know from this thumbnail is that yellow rows indicate HTTP redirects and purple bars represent images. The longer the bar, the longer it took for the resource to load.
So we can tell a few things from this waterfall image:
there are many redirects
there are many images
many images take a very long time to load, relative to other resources
When I look up https://muckenthaler.de/media/image/54/7c/cb/Sliderbild_Produkte_Steh_SItz_Tische_2.jpg in the response headers, I see at request 19 that there's a redirect to that image from https://muckenthaler.de/media/image/Sliderbild_Produkte_Steh_SItz_Tische_2.jpg.
Looking up that image in your source code, I see
<img src="https://muckenthaler.de/media/image/Sliderbild_Produkte_Steh_SItz_Tische_2.jpg"
alt=""
loading="eager">
Also note that this content is inside of something called <div class="hidden-elements">. These elements of class emotion--element are set to display: none so that the contents are not shown on screen, but loading="eager" on the images forces them to be loaded.
It seems like maybe your CMS (Shopware) is trying to eagerly preload images that will be used on other pages. That's not a terrible idea if you have a small number of lightweight images and users are very likely to navigate to those pages, but in this case it's loading dozens of images totalling over 30 MB. So definitely not recommended.
According to the CWV Tech Report, Shopware websites tend to only load 2 MB of images and have pretty good Core Web Vitals performance compared to other CMS and ecommerce platforms. That leads me to believe that there might be a misconfiguration on your end, or you may have installed a bad plugin.
First things first, a big thanks to Rick Viscomi for the research!
I found the answer which is basically Shopware 5 hidden elements, that can be shown and then be removed clicking the number next to the chain icon.
Here is a screenshot.
I have a web application that needs to serve a large amount of small images per page (up to 100). I can use caching to reduce calls to the database/backend, but there is a noticeable impact from having to make so many separate requests for the images themselves, as the images take some time to request and render, especially on slower connections.
What good practices exist for serving several images on a page? I'm aware of using a CDN (e.g. S3 + Cloudfront) to reduce bottlenecking on http requests and serve content from a closer geographical location, as well as potentially loading images/content via Ajax only once they come to the user's view in the browser. Are there other techniques that might provide significant performance gains for image-heavy pages? It doesn't really matter whether they relate to hardware, frontend or something else.
Thanks.
Loading 100 images in one page request increases the page load time as each image requires time to load in browser.
simple technique is to load only one default image , means the source of each 100 image should be common default image and only one image wont take much time to load.
when page loads all of its content then try to load each single image with help jQuery.
use lazyload jQuery plugin to load all images after page load.
like this
<img class="lazy" src="default.jpg" data-original="img1.jpg" >
<img class="lazy" src="default.jpg" data-original="img2.jpg" >
<img class="lazy" src="default.jpg" data-original="img3.jpg" >
.......
<img class="lazy" src="default.jpg" data-original="img100.jpg">
and in script use following code
$(document).ready(function(){
$("img.lazy").lazyload();
});
You may add expires header to each image which allows browser to cache them rather requesting them on next request.
hope it will help you.
You can use a different domain for images - these will be called on different threads than for the current domain.
You can also host your images on a web server optimized to serve static content - this will be faster than a dynamic server.
The above can be extended to several such domains - if the browser is set to have 4 threads per domain, each domain you add will parallelize to an additional 4 (which is also one of the benefits of using a CDN).
Another common technique that may apply is the use of CSS sprites - if you have a bunch of images that are commonly used together, you can put them all in a single image and use CSS to only show the bits that are needed where they are needed.
You can always combine the images into a single image and use CSS to display only parts of it at a time (commonly called CSS sprites)
Google also has a rather in depth article about how they implemented "Instant Previews" that covers some of the optimizations:
http://googlecode.blogspot.com/2010/11/instant-previews-under-hood.html?m=1
I was wondering if I have a JavaScript plugin, for example, of about 50Kb, does if I comment that out but I load the file anyway in the page, will be weight 50Kb to server side and browser side?
I mean 50kb of JavaScript, commented out at all, but loaded anyway, will afflict the page load performance as well as if it is not commented?
The browser will render the page faster, but obviously it won't make any difference for the server. The JavaScript, commented out or not, will still have to be downloaded.
I'll admit that I'm pretty new web development (only been coding for about a year) and especially green when it comes to JS / jQuery.
A specific web page I've built loads different data based on hovering over certain categories: country clubs, resorts, hotels, etc. When I built the site on my local machine, the javascript function was super quick. However, on the live site, it has a long delay before the data swap happens.
The URL is: http://preferredparkingsolutions.com/client_list.html
Which links to a javascript function at: http://preferredparkingsolutions.com/scripts/clientHover.js
Which replaces the display div (#client_list) by pulling data from a text file.
Is there a better / faster way of doing this?
Yes, this could be optimised by loading the content in up-front and caching it. Currently you are doing a HTTP request each for each and every hover - even if the user has hovered over that element before, since the AJAX responses aren't being cached. Doing this would be your quickest win.
However, I can't see any case at all for having the content live externally. Is there any reason you're against having the content physically in the page and just using show/hide methods? There's various benefits to this - SEO, for one thing, since Google will find the content.
this is the external page you are loading http://preferredparkingsolutions.com/client_list.inc.html and the content looks little and looks like its a static page then why not just load every thing upfront and then just hide and show div's ? as Utkanos suggested you will aslo have a SEO benifit and also its HTTP request each for each and every hover. if you still want to load it externally lost load it once and cache it and use the cached version to hide and show divs.
When cached, my starting page only needs to load one element (the "root document") - but then it needs some time until it's rendered completely:
alt text http://www.walkner.biz/_temp/firebug_net.png
The elements following are things loaded asynchronous via JavaScript.
Two questions:
Why does it take so "long" from loading the root document until the DomContentLoaded-event?
Does it make sense to load some not-so-important things asynchronously? Is it important to have the DmoContentLoaded-event as early as possible? Unfortunately there's not much documentation about that event, but I don't think it's the moment when the page is displayed, is it?
I'm not sure YSlow is gonna help him as that will download all elements for a page and run performance tests on them, whereas swalkner's problem is how long it is taking to render the HTML page itself when all other elements (images, CSS, etc) are cached.
At least that's what I think he's saying.
In the original question you said, "The elements following are things loaded asynchronous via JavaScript." but then listed nothing. What is loaded?
I would suggest checking for Javascript errors in the first instance. Then try removing some of your asynchronous loading calls one by one until you hit the bottleneck. In fact, remove them all, how long does the downloaded HTML take to render? Take that time and work from there.
Is your HTML document very big? Does it use lots of inline styles that could be in the CSS file?
Perhaps if you posted a link to the site then people would have a look at it.