Every responsive website development tutorial recommends using the display:none CSS property to hide content from loading on mobile browsers so the website loads faster. Is it true? Does display:none not load the images or does it still load the content on mobile browser? Is there any way to prevent loading unnecessary content on mobile browsers?
Browsers are getting smarter. Today your browser (depending on the version) might skip the image loading if it can determine it's not useful.
The image has a display:none style but its size may be read by the script.
Chrome v68.0 does not load images if the parent is hidden.
You may check it there : http://jsfiddle.net/tnk3j08s/
You could also have checked it by looking at the "network" tab of your browser's developer tools.
Note that if the browser is on a small CPU computer, not having to render the image (and layout the page) will make the whole rendering operation faster but I doubt this is something that really makes sense today.
If you want to prevent the image from loading you may simply not add the IMG element to your document (or set the IMG src attribute to "data:" or "about:blank").
If you make the image a background-image of a div in CSS, when that div is set to "display: none", the image will not load. When CSS is disabled, it still will not load, because, well, CSS is disabled.
The answer is not as easy as a simple yes or no. Check out the results of a test I recently did:
In Chrome: All 8 screenshot-* images loaded (img 1)
In Firefox: Only the 1 screenshot-* image loaded that is currently being displayed (img 2)
So after digging further I found this, which explains how each browser handles loading img assets based on css display: none;
Excerpt from the blog post:
Chrome and Safari (WebKit): WebKit downloads the file every time except when a background is applied through a non-matching
media-query.
Firefox: Firefox won't download the image called with background image if the styles are hidden but they will still download assets
from img tags.
Opera: Like Firefox does, Opera won't load useless background-images.
Internet Explorer: IE, like WebKit will download background-images even if they have display: none;
Something odd appears with IE6 : Elements with a background-image and display: none set inline won't be downloaded... But they will be
if those styles aren't applied inline.
HTML5 <picture> tag will help you to resolve the right image source depending on the screen width
Apparently the browsers behaviour hasn't changed much over the past 5 years and many would still download the hidden images, even if there was a display: none property set on them.
Even though there's a media queries workaround, it could only be useful when the image was set as a background in the CSS.
While I was thinking that there's just a JS solution to the problem (lazy load, picturefill, etc.), it appeared that there's a nice pure HTML solution that comes out of the box with HTML5.
And that is the <picture> tag.
Here's how MDN describes it:
The HTML <picture> element is a container used to specify multiple <source> elements for a specific <img> contained in it. The browser will choose the most suitable source according to the current layout of the page (the constraints of the box the image will appear in) and the device it will be displayed on (e.g. a normal or hiDPI device.)
And here's how to use it:
<picture>
<source srcset="mdn-logo-wide.png" media="(min-width: 600px)">
<img src="mdn-logo-narrow.png" alt="MDN">
</picture>
The logic behind
The browser would load the source of the img tag, only if none of the media rules applies. When the <picture> element is not supported by the browser, it will again fallback to showing the img tag.
Normally you'd put the smallest image as the source of the <img> and thus not load the heavy images for larger screens. Vice versa, if a media rule applies, the source of the <img> will not be downloaded, instead it will download the url's contents of the corresponding <source> tag.
Only pitfall here is that if the element is not supported by the browser, it will only load the small image.
On the other hand in 2017 we ought to think and code in the mobile first approach.
And before someone got too exited, here's the current browser support for <picture>:
Desktop browsers
Mobile browsers
More about the browser support you can find on Can I use.
The good thing is that html5please's sentence is to use it with a fallback. And I personally intend to take their advise.
More about the tag you can find in the W3C's specification. There's a disclaimer there, which I find important to mention:
The picture element is somewhat different from the similar-looking video and audio elements. While all of them contain source elements, the source element’s src attribute has no meaning when the element is nested within a picture element, and the resource selection algorithm is different. As well, the picture element itself does not display anything; it merely provides a context for its contained img element that enables it to choose from multiple URLs.
So what it says is that it only helps you improve the performance when loading an image, by providing some context to it.
And you can still use some CSS magic in order to hide the image on small devices:
<style>
picture { display: none; }
#media (min-width: 600px) {
picture {
display: block;
}
}
</style>
<picture>
<source srcset="the-real-image-source" media="(min-width: 600px)">
<img src="a-1x1-pixel-image-that-will-be-hidden-in-the-css" alt="MDN">
</picture>
Thus the browser will not display the actual image and will only download the 1x1 pixel image (which can be cached if you use it more than once). Be aware, though, that if the <picture> tag is not supported by the browser, even on descktop screens the actual image won't be displayed (so you'll definitely need a polyfill backup there).
** 2019 Answer **
In a normal situation display:none doesn't prevent the image to be downloaded
/*will be downloaded*/
#element1 {
display: none;
background-image: url('https://picsum.photos/id/237/100');
}
But if an ancestor element has display:none then the descendant's images will not be downloaded
/* Markup */
<div id="father">
<div id="son"></div>
</div>
/* Styles */
#father {
display: none;
}
/* #son will not be downloaded because the #father div has display:none; */
#son {
background-image: url('https://picsum.photos/id/234/500');
}
Other situations that prevent the image to be downloaded:
1- The target element doesn't exist
/* never will be downloaded because the target element doesn't exist */
#element-dont-exist {
background-image: url('https://picsum.photos/id/240/400');
}
2- Two equal classes loading different images
/* The first image of #element2 will never be downloaded because the other #element2 class */
#element2 {
background-image: url('https://picsum.photos/id/238/200');
}
/* The second image of #element2 will be downloaded */
#element2 {
background-image: url('https://picsum.photos/id/239/300');
}
You can watch for yourself here: https://codepen.io/juanmamenendez15/pen/dLQPmX
It seems browsers still download images even though they are directly or indirectly hidden with display: none property.
The only standard way to prevent this from happening I found is using loading attribute of the img tag:
<img src="https://cdn.test/img.jpg" loading="lazy">
All latest browsers support it except Safari and Firefox Android.
MDN img loading attribute specification.
Yes it will render faster, slightly, only because it doesn't have to render the image and is one less element to sort on the screen.
If you don't want it loaded, leave a DIV empty where you can load html into it later containing an <img> tag.
Try using firebug or wireshark as I've mentioned before and you'll see that the files DO get transferred even if display:none is present.
Opera is the only browser which will not load the image if the display is set to none. Opera has now moved to webkit and will render all images even if their display is set to none.
Here is a testing page that will prove it:
http://www.quirksmode.org/css/displayimg.html
Quirks Mode: images and display: none
When image has display: none or is inside an element with
display:none, the browser may opt not to download the image until the display
is set to another value.
Only Opera downloads the image when you switch the display to block.
All other browsers download it immediately.
The background-image of a div element will load if the div is set do 'display:none'.
Anyway, if that same div has a parent and that parent is set to 'display:none', the background-image of the child element will not load. :)
Example using bootstrap:
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
<div class="col-xs-12 visible-lg">
<div style="background-image: url('http://via.placeholder.com/300x300'); background-repeat:no-repeat; height: 300px;">lg</div>
</div>
<div class="col-xs-12 visible-md">
<div style="background-image: url('http://via.placeholder.com/200x200'); background-repeat:no-repeat; height: 200px;">md</div>
</div>
<div class="col-xs-12 visible-sm">
<div style="background-image: url('http://via.placeholder.com/100x100'); background-repeat:no-repeat; height: 100px">sm</div>
</div>
<div class="col-xs-12 visible-xs">
<div style="background-image: url('http://via.placeholder.com/50x50'); background-repeat:no-repeat; height: 50px">xs</div>
</div>
If you make the image a background-image of a div in CSS, when that div is set to 'display: none', the image will not load.
Just expanding on Brent's solution.
You can do the following for a pure CSS solution, it also makes the img box actually behave like an img box in a responsive design setting (that's what the transparent png is for), which is especially useful if your design uses responsive-dynamically-resizing images.
<img style="display: none; height: auto; width:100%; background-image:
url('img/1078x501_1.jpg'); background-size: cover;" class="center-block
visible-lg-block" src="img/400x186_trans.png" alt="pic 1 mofo">
The image will only be loaded when the media query tied to visible-lg-block is triggered and display:none is changed to display:block. The transparent png is used to allow the browser to set appropriate height:width ratios for your <img> block (and thus the background-image) in a fluid design (height: auto; width: 100%).
1078/501 = ~2.15 (large screen)
400/186 = ~2.15 (small screen)
So you end up with something like the following, for 3 different viewports:
<img style="display: none; height: auto; width:100%; background-image: url('img/1078x501_1.jpg'); background-size: cover;" class="center-block visible-lg-block" src="img/400x186_trans.png" alt="pic 1">
<img style="display: none; height: auto; width:100%; background-image: url('img/517x240_1.jpg'); background-size: cover;" class="center-block visible-md-block" src="img/400x186_trans.png" alt="pic 1">
<img style="display: none; height: auto; width:100%; background-image: url('img/400x186_1.jpg'); background-size: cover;" class="center-block visible-sm-block" src="img/400x186_trans.png" alt="pic 1">
And only your default media viewport size images load during the initial load, then afterwards, depending on your viewport, images will dynamically load.
And no javascript!
If so is there a way to not load the unnecessary content on mobile
browsers?
use <img src="" srcset="">
http://www.webdesignerdepot.com/2015/08/the-state-of-responsive-images/
https://caniuse.com/#feat=srcset
To prevent fetching resources, use the <template> element of Web Components.
Use #media query CSS, basically we just release a project where we had an enormous image of a tree on desktop at the side but not showing in table/mobile screens. So prevent image from loading its quite easy
Here is a small snippet:
.tree {
background: none top left no-repeat;
}
#media only screen and (min-width: 1200px) {
.tree {
background: url(enormous-tree.png) top left no-repeat;
}
}
You can use the same CSS to show and hide with display/visibility/opacity but image was still loading, this was the most fail safe code we came up with.
Hi guys I was struggling with the same issue, how to not load an image on mobile.
But I figured out a good solution. First make an img tag and then load a blank svg in the src attribute. Now you can set your URL to the image as an inline style with content: url('link to your image');. Now wrap your img tag in a wrapper of your choice.
<div class="test">
<img src="data:image/svg+xml,%3Csvg%20xmlns=%22http://www.w3.org/2000/svg%22/%3E" style="content:url('https://blog.prepscholar.com/hubfs/body_testinprogress.gif?t=1495225010554')">
</div>
#media only screen and (max-width: 800px) {
.test{
display: none;
}
}
Set the wrapper to display none on the breakpoint where you dont want to load the image. The inline css of the img tag is now ignored since the style of an element wrapped in a wrapper with display none will be ignored, therefore the image is not loaded, until you reach a breakpoint where the wrapper has display block.
There you go, really easy way not to load an img on mobile breakpoint :)
Check out this codepen, for a working example: http://codepen.io/fennefoss/pen/jmXjvo
No.The image will be loaded as usual and will still use the user’s bandwidth if you are considering the mobile phone user bandwidth saving.What u can do is to use media query and filter the devices that you want your image to be loaded.Your image must be set as a background image of a div,etc and NOT an tag since the the image tag will load the image regardless if the screen size and the media query set.
we're talking about images not loading on mobile, right? so what if you just did an #media (min-width: 400px){background-image:thing.jpg}
wouldn't it then only look for the image at above a certain screen width?
Another possibility is using a <noscript> tag and placing the image inside the <noscript> tag. Then use javascript to remove the noscript tag as you need the image. In this way you can load images on demand using progressive enhancement.
Use this polyfill I wrote to read the contents of <noscript> tags in IE8
https://github.com/jameswestgate/noscript-textcontent
The trick to using display:none with images is to assign them an id. This was there is not a lot of code needed to make it work. Here is an example using media queries and 3 stylesheets. One for phone, one for tablet, and one for desktop. I have 3 images, image of a phone, a tablet, and a desktop. On a phone screen only an image of the phone will display, a tablet will display only the tablet image, a desktop displays on the desktop computer image.
Here is a code example to make it work:
Source code:
<div id="content">
<img id="phone" src="images/phone.png" />
<img id="tablet" src="images/tablet.png" />
<img id="desktop" src="images/desktop.png" />
</div>
The phone CSS which doesn't need a media query. Its the img#phone that makes it work:
img#phone {
display: block;
margin: 6em auto 0 auto;
width: 70%;
}
img#tablet {display: none;}
img#desktop {display: none;}
The tablet css:
#media only screen and (min-width: 641px) {
img#phone {display: none;}
img#tablet {
display: block;
margin: 6em auto 0 auto;
width: 70%;
}
}
And the desktop css:
#media only screen and (min-width: 1141px) {
img#tablet {display: none;}
img#desktop {
display: block;
margin: 6em auto 0 auto;
width: 80%;
}
}
Good luck and let me know how it works for you.
I put embed codes of videos in custom field, every embed code (video) from every site have a different size..
there is a way to set a specific size for all embed videos without change the sizes in the embed codes?
i mean just copy and past the embed code with all parameters and then some code will change the videos to specific size?
You can do that with CSS or JS. For example, you can:
Have specific width and height for iframe in css
Have a JS script that will resize your iframe dynamically, for example on document.ready.
An example of the CSS would be something like:
.content iframe { width: 600px; height: 480px; }
An example of the JS would be something like:
jQuery(function($) {
var iframes = $('.content iframe');
iframes.css('width', 600);
iframes.css('height', 480);
});
Please, note that these examples would apply to iframes that are within an element with class "content", for example <div class="content">.
Is it possible to set the default zoom level on a site? For instance, could I code my site in such as a way that it is zoomed to 125% when a user opens it?
My website body has this code
<body ID="phpbb" class="section-{SCRIPT_NAME} {S_CONTENT_DIRECTION}">
How to put this zoom code inside?
Add zoom: 125%; to body style
body {
color: #536482;
background-color: white;
zoom: 125%;
}
This does not directly answer your question, but is an alternative that I recommend considering.
If you use relative sizing for your page (such as em), then you can set the base size of the site in one place, and the whole page will scale up and down accordingly.
For instance, if I want 125% of default size:
body { font-size: 1.25em }
Then, suppose I want a reasonable amount of margin around a header <div>:
#header { margin: 1em }
If I then go back and change that base size on the body to something else, the margin on my header will scale with it. If you do your entire page in relative units, this becomes very easy to do.
You might want to check the zoom CSS attribute. Bear in mind however that it is part of CSS3 and that, therefore, you might find it to behave oddly on old IEs. This is also completely separate from the interface zoom.
webView.setInitialScale((int) getResources().getDimension(R.dimen._50sdp));
webView.getSettings().setLoadsImagesAutomatically(true);
webView.getSettings().setJavaScriptEnabled(true);
webView.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
webView.loadDataWithBaseURL(null,htmlContent,"text/html","UTF-8", null);
webView.getSettings().setBuiltInZoomControls(true);
webView.getSettings().setSupportZoom(true);
webView.getSettings().setDisplayZoomControls(true);
webView.getSettings().setDefaultZoom(WebSettings.ZoomDensity.FAR);
I am developing a webpage in which I am setting background with help of div but my problem is that when the resolution of screen changes the image does not fit properly , it shows blank space on both side of screens on large screens.
Is there a way with which I can make a standard case which shall run for all screens .
This is how I am setting my div
mheaderimgs {
width:1007px;
margin:auto auto;
height:auto;
}
CSS backckground-size property,
background-size:contain;
for more reference, see
http://www.w3schools.com/cssref/css3_pr_background-size.asp
width:100% would strech it, If you make it a slightly bigger image it would shrink it in most cases only making you need 1 image.
As far as Im aware, there is no none-javascript method to get the size of the screen and then compare to set sizes
Php doesn't know how big the clients screen is. Consider javascript or Media queries
.
May be you can try this (CSS3 property) :
background-size: cover;
Otherwise, I think you can do it in javascript.
i have a button in html that has a background image and text overtop of it, how can i disable the selecting of that text so it looks more "seamless"?
echo '<td width="130" height="30"'. "onClick='document.location = ".'"'.$value.'";'."'><center>".$key."</center></td></a>";
Use this css:
#defaultPointer{
cursor:default;
}
for this div:
<div id="defaultPointer">
<p>
hello world
</p>
</div>
Just a sample, but it should totes McGoats make it more seemless. I've done the same with a site before.
In your case you'd probably just add the id to the td you've got there.
Hope this helps.
Two ways of doing this
- Render the text as image as we have email in Facebook
- Overlay it with a Div with semi transparent image as a background
If I have understood your question correcty, you want it to behave like a button, just add to your "td" a style:
style="cursor:pointer;"
To style the mouse pointer, you need to use the cursor CSS style.
.normalpointer {
cursor:default;
}
This works in all browsers. (There are some pointer types that can be styled which do have cross-browser issues in older browsers, but default definitely works everywhere)
Disabling the ability to select text is slightly more complex: you need to do a few things, because browser support is varied.
For browsers that support doing it via CSS, you need the following:
.unselectable {
-webkit-user-select: none;
-khtml-user-select: none;
-moz-user-select: none;
-o-user-select: none;
user-select: none;
}
ie user:select:none; plus a bunch of browser-specific variants on the same. Some of those browser-specific variants can probably be dropped now, as support has improved, but if you keep them anyway, you'll be able to support people who haven't upgraded their browsers in a while.
I believe the above also works in IE9, but older versions of IE definitely don't support it. For those, you need to add the following attribute to the element you want to make unselectable: unselectable="on"
Thus, an unselectable div in all browsers would look like this:
<div class='unselectable' unselectabnle='on'>....</div>
(with the class referencing the stylesheet above)
An alternative to the user-select CSS style would be to use ::selection CSS. This allows you to style how text looks when it's selected. You could use this for example to set the selection text to look the same as normal text, which would allow the text to still be selected, while not being actually visibly changed:
.myclass::selection {
background: transparent;
}
again, you may need some vendor-specific stylesheets for to support older versions of some browsers -- eg:
.myclass::-moz-selection {
background: transparent;
}
Hope that helps.