Preload image CSS - css

I have problem with a preloaded image on Firefox. On (webkit) Chrome/Safari it looks fine.
Let's take a look.
I have :hover load image
the css file:
.zz{background:url(../img/guzik_01_ofirmie_PL_A.png) no-repeat; height: 1px; width: 1px; position:absolute; }
li#ofirmie{background:url(../img/guzik_01_ofirmie_PL_B.png) no-repeat; height: 44px; width: 108px; position: absolute; z-index: 1000;}
ul.menu li#ofirmie:hover {background:url(../img/guzik_01_ofirmie_PL_A.png) no-repeat; height: 44px; width: 108px; position:absolute;}
and HTML
<div class="zz"></div>
<li id="ofirmie" ></li>
Why doesn't Firefox load the image from the cache, rather than from server?
How can I fix it?

As long as it's possible don't use two images. Use CSS Sprites technique. Then you just operate on background-position property instead of different images.

Or you can try using the jQuery preloadCssImages function, this will make sure your images are loaded into the cache before displaying and thus making your page much smoother;
http://www.filamentgroup.com/lab/update_automatically_preload_images_from_css_with_jquery/

Related

why do sprites not work with a general background?

So for my website hostup I tried to add sprites since I had over 25 images and google pagespeed complained. I solved my sprire not displaying issue, but I am not sure why. Why is it that you have to load the image in each and everysprite, to waste bandwith and slow down pagespeed?
.sprite {
background-image: url(../img/spritesheet.png);
background-repeat: no-repeat;
display: block;
}
.sprite-backup_icon {
width: 60px;
height: 60px;
background-position: -5px -5px;
}
.sprite-cpanel_icon {
width: 60px;
height: 60px;
background-position: -75px -5px;
}
.sprite {
background-image: url(../img/spritesheet.png);
background-repeat: no-repeat;
display: block;
}
.sprite-backup_icon {
width: 60px;
height: 60px;
background: url(../img/spritesheet.png);
background-position: -5px -5px;
}
.sprite-cpanel_icon {
width: 60px;
height: 60px;
background: url(../img/spritesheet.png);
background-position: -75px -5px;
}
html code
<div class="sprite-backup_icon"></div>
So the 2nd. works just fine, but the 1st. does not display any image, Just a blank image with the defined width and height, why is this?
To answer your first question:
If the browser finds an image in a Style Sheet, it will download it and then store it in your browsers cache. The next time that same image is found/requested in a Style Sheet from the same URL (even during the same initial page load), it will be served from cache. NOT re-downloaded. So while you may have spritesheet.png 3 times in your Style Sheet, it is only downloaded once and not wasting bandwidth or page loading speed.
It is because of this caching feature that sprites are favoured in providing things like icons and other smaller images.
For your second question on why your first CSS example does not work, it could be any number of issues ranging from a simple typo, or all the elements you are wanting to use the sprite with not having the sprite class.
In order to properly help you with this problem, we need to see your HTML that goes along with the posted CSS. Please make an edit your question and add your HTML as a code snippet.

How I can detect a 404 image in css or less?

I have a banner on a website with the following less/css class:
.element-link {
display: block;
background: url('url to image') repeat-x center center;
height: 71px;
background-size: cover;
cursor: pointer;
width: 100%;
}
and the html
<a class="element-link" href="url to other site" target="_blank"></a>
But, when there is no images on url('url to image') (This is a border case, but we must to resolve it), the banner doesn't appears (that's good, it gave us the flexibility to remove banners simply deleting the image in the server), BUT the link continues to work.
EDIT: So, what I need to do is: detect that there is no image on
background: url('url to image') repeat-x center center
and in that case change the height: 71px; to height: 0px;
I know that I can do this in javascript, but because the site is not mine, I want to know if I could do this in less before offer them a javascript solution.

HTML5 boilerplate background-image doesn't show

I'm making a website with HTML5Boilerplate, but every time I use the css background or background-image property, the image doesn't show up.
Folders:
root/css/style.css
root/img_files/logo.png
My css code looks like this:
#logo {
position: absolute;
left: 20px;
top: 10px;
width: 164px;
height: 42px;
background: url(../img_files/logo.png);
background-repeat: none;
}
My stylesheet is properly added to the page:
I can't add a single background image to the objects on the page. HTML5Boilerplate has been installed, so maybe that't the problem, I'm not sure. Do you know why correct CSS and HTML doesn't display the images?
Change
background-repeat: none;
to
background-repeat: no-repeat;
Or just use
background: url(../img_files/logo.png) no-repeat;
I've just come to the same problem and discovered that in case you'll change ID from #logo to anything else (in HTML and CSS of course), then the same code will start to work. Can't say what has been "blocking" #logo to be used, but for now I don't have enough time to discover where the problem is.
Solution for now is to use anything else than #logo, eg. #logoTop or #siteLogo
Hope that helps.
EDIT: It was a selector typo problem which caused browser had ignored that. Weird was it had not happened when selector was changed to some other name than #logo. Please note that #logo:visible typo (instead of visited)
#logo, #logo:link, #logo:visited,
#logo:active, #logo:focus, #logo:hover
{
display: block;
width: 340px;
height: 150px;
background: url(../images/design-elements.png) 0 -300px no-repeat;
}
I had the same problem & found out that if without the width & height property, image will not display.

Firefox CSS image box

This CSS code does work in all browsers except FireFox. Why ? How can I fix it ?
.img_box {
width: 110px;
height: 160px;
background-repeat: no-repeat;
background-position: center center;
background-image: url('https://www.google.com/images/srpr/logo3w.png');
}
Thanks in advance.
EDIT:
Here is the HTML that I want to use:
<img class="img_box" />
When Firefox encounters an image without a source, it replaces the image with its alt text. I personally find this extremely annoying, as it means I can't test layouts unless I specifically create placeholder images, and should those images be unavailable for any reason the layout completely breaks.
Unfortunately, I have yet to find a solution to this problem.
In your case, however, you would be much better off using a div and adding display:inline-block to your CSS, instead of using an image.
solution1:
.img_box {
width: 110px;
height: 160px;
background-repeat: no-repeat;
background-position: center center;
background-image: url('https://www.google.com/images/srpr/logo3w.png');
display: block;
}
solution2:
<div class="img_box"></div>

CSS Image Replacement, but SHOW text when Images are disabled

I have recently put together a working navigation bar.
I'm pleased with it, but unfortunately it isn't accessible.
When images are OFF, I would like to show replacement text in its place.
Is this easy to achieve with my example: http://pastebin.com/hXth7FSK ?
Many thanks for any pointers.
Michael
You can absolutely position a span inside the element so that it covers the text as this post from Dave Shea explains:
<h3 id="header" title="Revised Image Replacement">
<span></span>Revised Image Replacement
</h3>
/* css */
#header {
width: 329px;
height: 25px;
position: relative;
}
#header span {
background: url(sample-opaque.gif) no-repeat;
position: absolute;
width: 100%;
height: 100%;
}
The only limitation is this will not work for partially transparent images.
If you want to use background-images (I prefer background-images as well for navigations) you could absolutely position a blank image over it by adding this CSS: position: relative; z-index: 100; to all of the navigation elements with background images and then putting this in them:
<img src="pixel.gif" alt="Text to display when images are off" style="width: 100%; height: 100%; position:absolute; top: 0; left: 0; z-index: 50;" />
Then, when the images are off, the alt text of the blank image will show. This image will be under the element, but when images are off, you will be able to see the image's alt text. Also, this will work for partially transparent background images.
You can use this pixel.gif image.
Hope this helps.

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