Few sites for example smashingmagazine.com , the structure loads first and then the
contents loads into it, the images,text and all,is ajax behind this?
php flush and buffer is good to go with , but what is behind this , can someone throw some light?
The content always loads first. Some parts just load later if they are in external files. Sometimes that causes the content to reflow (e.g. if the content includes images without explicit dimensions set), sometimes it doesn't. The text loads later because it depends on #fonts.
Related
Assume you have 75 div's that have data-id="{some number}" attribute. The overall page size is unfortunately big, very big.
There are many repetitive HTML snippets in my HTML document like image tags or links. These images/links' only changing portion is the id.
The HTML document is quite long, these snippets contribute to the overall size of the document.
I can run a javascript when dom is ready, but the user experience will be:
- wait the page loads, and start seeing nodes etc,
- page loads,
- extra snippets show.
I can make the top container DIV to hide until the page loads but
- worried that google search bot could realize the div is hidden and skip the content (or does it?)
- the users won't be able to see the content while the page is loading.
What ideal is to load the page in HTML without much extra markup for google search bot, and add extra elements while it's loading with javascript.
Any tricks that I can try that comes to your mind to accomplish this?
Thank you.
The best performance and user experience is to do as much work as possible on the server, then send efficient HTML and allow the browser to display the page as it's received. Sending say a single DIV container, then using script to clone it 70 or 80 times will be slower (probably a lot slower for some users).
Hiding content completely until your script has finished is the worst solution - users are left with a blank (or minimal content) page, waiting for something to happen.
The vast bulk of most pages is script and images, replacing HTML with scripting really is playing at the margins. e.g. this page has 90KB of HTML and 264KB of script, images and css. Apple's home page has 12KB of HTML and around 800KB of script, css and images.
Browsers show content progressively as it's received because that's how they evolved over many years on the web. Users prefer to see something rather than nothing, and to start viewing content while the rest loads (it's all about the content, not about fancy layouts or effects). Try to work with browser behaviour and features rather than against them.
You can greatly help the browser by specifying sizes for images and having an efficient layout. That way the layout won't change much as new content is received.
Depending on other page content, you could run your script on DocumentReady as opposed to onload.
DocumentReady runs after the page downloaded and the DOM rendered, but before images are retrieved.
I believe that there is an official DocumentReady event somewhere, but I still have to support IE6 on my pages, so I use a busy loop to watch the DOM.
First of all: I hope the following question is not too generic.
I have a small problem and I cant think of a good solution and I was hoping some1 here is able to help me.
This is my situation:
I am using AJAX to dynamically load pages. My main site is index.php and once I click on a navigation link, the AJAX script replaces the content of index.php with new content and adds a hash tag to the URL. For instance:
I click on the link to about.php, the script adds #about.php to the URL and loads content from about.php into index.php. It works great :) However, there is a small issue that I would like to resolve:
Lets say we start by navigating to index.php#about.php directly - this means the content of index.php is visible for 2,3 seconds and than gets replaced with content from about.php. And I would like to avoid that.
I came up with a few ideas, but they are all not really great:
1) Hide content -> than make AJAX call -> on completed AJAX show content again
Downside: The content is still visible for a second.
2) Hide content with CSS and show it after AJAX call
Downside: This would work perfectly, but users without Javascript (and the GoogleBot) will see an exmpty page only.
3) Use an empty index.php and put the content of it in main.php and automatically load main.php via AJAX on page load.
Downside: Would work too, but again, users without JS and GoogleBot will just see an empty page when the visit index.php
Thats all I can think of and all three solutions are not good, because I am worried the SEO value will dramatically decrease when I have an empty index.php (I could accept that users with no JS get nothing to see).
p.s. I read somewhere that when you have display:none in an external css file and block it with robots.txt, GoogleBot wont know the difference, but I am worried thats maybe not the case? Any1 got some experience?
Edit: I guess my whole question comes down to this:
Do you think hiding the whole content of index.php with CSS (and than show it with JS), will be a huge no-go for SEO or will it be okay with GoogleBot (afterall the content is still in the source, but not visible to the user)?
If you used query strings instead of the hash you could have index.php load the correct content at the server level.
A plugin like history.js can help you push URLS to the browser so that you still get your ajax browsing.
Wow where to start...first of all the page 'blink' I'll call it is 2-3 seconds for you but it is completely dependent on the users computer, how fast it executes the javascript, and how fast the AJAX call returns so you could have a much larger delay.
Second I wouldn't worry about Googlebot seeing any of the ajax content. While it's true googlebot does try to fiddle with some javascript it won't make the ajax call like a normal browser would. I'd be very surprised if Googlebot ever saw any of your Ajax loaded data.
Googlebot does a fantastic job of figuring out what content is delivered via html/css to a user when they visit your page. It also figures out if something is displayed or not and does a good job of deciding if that content is just stuffing or is something that really matters.
You're worried about what someone without javascript will see when the entirety of navigating your site is based in javascript. This doesn't seem to reconcile.
You've got PHP available. My suggestion is to forgo the AJAX stuff you're trying to do and do it in PHP. You can just as easily script the same behavior in PHP as you can in AJAX.
SEO NOTES:
If you're looking for solid SEO results I suggest making the static (non-javascript version) page as SEO friendly as possible. I like to 'pick the low hanging fruit' like making sure the page has one and only on H1 and that it has the most important keywords in it. seomoz is one of the best sites I've found for seo information.
Is there a way to load the entire contents of a page into a javascript variable? (the page is not properly formatted HTML.) Ie store the page contents as a string in a variable. It only needs to work with Firefox.
I have some javascript running in one firefox tab that accesses the content of a page in another tab (the target window). Normally the content of the target is an HTML page so I can get at its content like this...
targetWindowName.document.getElementsByTagName("html")[0].innerHTML;
However I have come across a page that is not in proper HTML and so the above doesnt work.
(The actual content of this awkward page is JSON. I know this would be best loaded up with AJAX or something but I have a framework already setup to process HTML pages and it would be very handy if I can treat this particular (one off) page just like a regular HTML page.)
Thanks
Guess you can use:
win.document.documentElement.innerHTML
Read the file into a variable. Like you would any text file.
So, Page "A" has code that goes out and gets the HTML page contents and loads it into a variable.
I've read that it is better to place your <script> tags at the end of the document. The argument for doing this appears to be that the browser will stall rendering the page below a script tag until it has loaded and and executed the script. If your script tag is at the top of the page, rendering is stalled for a while, which is bad.
However, I am not sure if this is really true any more.
Looking around, I normally see the following locations...
In the <head> of the page or Just inside the <body> tag
Stackoverflow is an example of a site that puts the script tags in the head, and since they are normally rather obsessed with performance, I am starting to wonder if position in the page is important at all.
Last thing in the body element
The other common place to put javascript appears to be right at the very end of the <body> element. I am assuming this means that the page can render while the javascript downloads and gets on with doing its thing.
But which is better?
Does anyone have any thoughts or advice on this? I am looking to try and get our pages to perform and appear to the user as quickly as possible.
Does it matter? What are the advantages of being at the top of the page? Bottom of the page?
It really depends.
There is no catch all answer for this because it depends on what your javascripts are acting on.
Putting scripts at the end of the page is sometimes needed if your acting on a DOM element that needs to be loaded for the script to run. Say you want to focus on a control and your script is:
var mytext = document.getElementById("mytext2");
mytext.focus();
Well in this case you would want it to execute at the end of the page, after mytext2 control has already been loaded by the browser. This is less important for script blocks that only contain functions that are called by events.
If you have a big .js file that contains libraries of functions you may also want to put that at the end of the page so the browser will load the page faster before loading the large .js file.
Google analytics suggests putting their tracker at the end, to make sure the page has been delivered before you count the hits, but in some cases it suggests putting the script into the header too, it works both ways.
So, rule of thumb for me is, HEAD scripts for everything except things that execute in-line and act on DOM objects, or large scripts that you want to load after the page.
Rick Strahl just wrote a great blog on placement of Javascript in .net too:
The only validating way is to include it on the top (in the <head> section), but in the bottom will be faster to load - the rest of the page will load faster if you have script near the bottom, giving the user better response and making the experience better.
The problem is that most web browser stop rendering the HTML of the page until they've fetched and parsed all JavaScript code so far. So if you have a slow-loaded .js file included in the <head>, no HTML will be rendered and images will not even start to download before the .js have been downloaded and parsed, therefore frontend engineers propagate for putting the scripts as far down in the code as possible.
I usually just set a far-future Expires header for my .js files so they are cached in the browser for a long time and then include them in the <head> section. This gives good performance and doesn't look ugly :-)
But if you are serving external .js libraries (that are on other servers than your own), you will probably want them in the bottom because you can't change the Expires-header for other servers and you canät know that the other server always will be responsive.
yeah. Put Scripts at the Bottom
I think the size of the js file is much more important than the location of javascript. I always set highter number of the con-current connection to make sure they download in parallel.
I believe it's better to place script tags just before the closing body tag. Because:
Elements are blocked from rendering if they are below the script.
In IE6, IE7 resources in the page are blocked from downloading if they are below the script.
From this article. Also Yahoo's performance rule 6 is Move Scripts to the Bottom
Google Analytics always used to say to put the script tag at the bottom of the page. I believe the rationale was that if the Google servers ever went down, the page would fail to load if it were in the head (only for IE probably).
I was just using the plugin "Yslow" for Mozilla Firefox, and it told me that I should put JavaScript at the bottom. I have heard this before but haven't really thought about it too much. Is there really an advantage in putting JavaScript at the bottom of a web page compared to the top?
It'll allow the web page to load visibly before executing JavaScript, which makes sense for things like Google Analytics, which don't need to happen before the page loads.
You may also want to look into things like jQuery, prototype, etc and attach to the "ready" handler, which executes JavaScript code after the DOM has been fully loaded, which is an appropriate place for much JavaScript code.
Assuming you aren't running on a CDN or aren't serving your JS from a separate sub-domain or server, it will load synchronously and force your HTML content to wait until it has downloaded the files. By placing the JS at the bottom of your page before the closing </body> tag, you are allowing the HTML to be parsed prior to loading the javascript. This gives the effect of faster page load times.
If you have static html content and a lot of javascript, it can make a difference in perceived page load time since the html will load first giving the user something to look at. If you don't have much javascript, or the existing page content relies on the javascript to be useful, then this is not as useful practically-speaking.
I want to bring update to this topic, google has recently introduced async snipped http://support.google.com/analytics/bin/answer.py?hl=en&answer=1008080&rd=1 which can be added for your site to bring e.g. google statistics support. It should be placed bottom of the <head> section for best performance. The point is that this increases likely hood of tracking beacon to be sent before user leaves the page.
Also it should be located there if you want to verify your site in google webmaster tools using your google analytics.
Other than that, same rules still applies basically - javascript at bottom for "fast" loading of the page. I used quotes because I dont count page fully loaded until javascript finishes ;-)
Yes, the page will load the content and render it before loading and executing javascript, and the page will, as a result, load faster.
TOP
When you put your JavaScript at the top of the page, the browser will start loading your JS files before the markup, images and text. And since browsers load JavaScript synchronously, nothing else will load while the JavaScript is loading. So there will be a timeframe of a few seconds where the user will see a blank page, while the JavaScript is loading.
BOTTOM
On the other hand, if you place your JavaScript at the bottom of the page, the user will see the page loading first, and after that the JavaScript will load in the background. So if, for example, your CSS & HTML takes 5 seconds to load, and your JavaScript takes another 5 seconds, putting our JavaScript on the top of the page will give the user a “perceived” loading time of 10 seconds, and putting it on the bottom will give a “perceived” loading time of 5 seconds.
Taken from Demian Labs.
It allows all the DOM elements to fully load before loading the Javascript which addresses them. This standard is also part of Visual Studio.
Placing scripts at the bottom of the element improves the display speed, because script compilation slows down the display.
Yes including the javascript at the bottom of the page really quickens the loading of the page. Since browser executes things synchronously it impacts the page loading if it is placed at the top of the page. If it is placed at the bottom of the page, the page would have loaded the entire markup by then when the browser starts loading the javascript giving a better experience to the user.
It's advisable to put all inline scripts at the end to improve performance, you don't want your users to be staring at a blank white screen while the script renders. You can use defer attribute eg. to prevent link scripts from delaying your html rendering.