how to make browsers download hidden divs content in advance - javascript

After playing with hidden divs (display:none), I've noticed that the browser does not seem to bother downloading any images/flash files that are in that div, until the divs are changed to visible.
The problem with that is, on most users machines, when viewing a hidden div, there seems to be a good couple of seconds in waiting time for the browser to download images or swf files, etc... which == no happy user.
Is there any way to make the browser download the hidden div's content, while it's hidden, and not when it's been set to visible?
In JS or jQuery maybe?
Thanks

Don't use display:none; to hide images.
Try setting the following to hide the content.
height:0;
width:0;
overflow:hidden;
You could also try positioning the content off the screen with absolute positioning.
position:absolute;
left:-1000px;

Here are some options:
Start with the DIV visible, then add the hidden style using jQuery after page load, or after the browser has already fetched the images. This will likely happen so quickly no one will even notice the change.
Position the DIV off screen initially while things load, and fix the dimensions of the DIV (height/width) to be very small so that it doesn't take up visible space.
Use jQuery to load the content of the DIV at the same moment you want to make it visible--fetch the images on demand. i.e. $('#yourDivId').html('[html goes here]');
Use visible:hidden instead of display:none (but beware that it will still occupy space, so this may not work in all situations). You might place a copy of the image at the bottom of the page where layout won't be affected, but will still be fetched and browser-cached for when you make your other location visible.

One way which you can try is, instead of hiding them position absolutely with large negative left position and with minimum dimension may be 1 or 0.

Related

How to make space for images before they load?

I am currently building a portfolio website for myself. I have an array of projects that are flex and change size as the window changes size, once they get to a min-width they wrap over to the next line. My problem is that when the website is loaded for the first time without a cache, the images haven't loaded yet and the height of their container doesn't fit them. This causes a lot of overlap, but when the page is refreshed and there is a cache it fixes itself. An example is shown here:
The cache problem.
My idea to fix this was to make a min-height, but since its responsive and the size of the container changes, I don't know how to set the min-height. I was thinking of setting it to a mathematical relation to the width of the view port window, but wasn't sure if I had the skills to make that work. I will happily attach the code if needed.
If you want to preserve space for an existing image you can wrap it into a div and adjust this div's dimensions any way you like. For example, you can set min-height. Or if the image height varies you can use loading indicators (gif loading animations) with their own dimensions, and when your images finally load, you can replace the gifs with the actual images using js onload event
To make space for images before they load you need to give each image a corresponding value(*) of its height and width.
( * - in good coding practices, this is actually a requirement ! )
For example ::
<img src=[url] width=180px height=300px>
If you want a fast, stable, responsive, robust and absolutely solid page - Never leave images, tables and table-cell columns without a 1. width and 2.height specs.
Even if they are flexy, you are highly encouraged to at least use relative size (%).
<img src=[url] width=60% height=100%> /*relative::Let's say this set of images is in a
div who's css height is 300px. The images width given as 60% matches exactly its pixel
width, which is 180px.*/
You will immediately notice a tremendous improvement of your page performance and have away better experience working with them. Depending on the complexity of elements a ten fold improvement of the render speed may be achieved.

Loading new content into a responsive slider

How does this slider reload new content as the page is resized?
http://www.herschelsupply.com/
I stumbled across this whilst shopping and their slider is a good facsimile of what I want to create for my own site. Their slider loads new content at a certain point when the window is resized. I have had troubles doing that using BxSlider because I am new to JS.
More info
The problems I have had are these:
I can use css media query or jQuery to hide certain slides, but they remain in the DOM so the slider still displays them in the pager and sometimes it just stops rotating/breaks.
If I create two different sliders to be loaded at different widths the change does not occur as the page is resized. Also this seems wasteful.
If I remove and replace elements from the DOM on $(window).resize(), I am not sure how to return them to the DOM if the window is resized back and forth continuously.
Overall I am just asking what approach you would take to do this? Im sorry if this is verging more towards discussion than a specific question, but I'm not sure where else to ask.
The website you showed simply has two completely separate slideshows. One is hidden and another is shown when the window resizes.
<div id="slider-one" class="hide-for-mobile">
/*Slider here*/
</div>
<div id="slider-two" class="show-for-mobile">
/*Slider here*/
</div>
Then in your media query for mobile...
.hide-for-mobile {
display: none;
}
.show-for-mobile {
display: block;
}
Now, as for a solution that's more along the lines of what you were trying to do... What you need to do is get away from HTML <img> tags. Instead, your sliding elements should be <div>'s with a CSS background image. In this way, in your media queries you can change the background image of the <div>'s. I am unsure whether or not the slider you are using can support this, some are dependent on sliding an actual HTML <img> tag. Some can slide whatever you want. You should be able to manage what I've described with Flexslider (a quick google search will get you where you need to be).

Prevent snapback to original position in iScroll4

I'm using iScroll4 to make a certain element scrollable in my webpage but it snaps back to the original position once you release the mouse/touch. How do I make it stay instead?
I think that I have figured out why this happens. I had iscroll4 working in a Phonegap app that I was building, and then broke it after changing some CSS. At the time, I didn't realize what I had done and I spent a long time hunting for a Javascript solution.
Finally, I noticed that when I tested it in a browser, there was a scrollbar for the list where I was using iscroll4. And when I tried to scroll, the scrollbar thumb changed size. That is why it was snapping back. The browser made the wrapper div big enough to hold the entire list, so whenever I tried to scroll, there was no hidden data so I triggered the pull-up event and then the browser resized the div.
I had to change the CSS to include overflow:hidden and it started to work again. I tried overflow:hidden on the ul tag and the scroller div but that didn't work. It has to be on the wrapper div.

Make a div fall off the page

So I have been playing with jQuery for a good time now and I'm trying to get an effect to work properly. I have a main square div in the middle of the page and when someone clicks a link I want the box to look like its falling off the page and disappear, revealing a new page behind it. I'v been playing with the easing plugin but I can seem to get what I want to work. Basically I have the div's top margin or just top distance increased to a large number. However, this just makes the div fall but it also expands my page and its just much lower on the page. I basically want the div to fall out of site and not change the dimensions of the site. Anyone know how to do that?
Thanks!
Danny
To prevent your page from redimensionning upon clicking on your link, add overflow:hidden to your div container 's css properties.
also, make sure you hide the div when the animation ends.
$('a').click(function(){
$('#thediv').parent().css('overflow','hidden');
$('#thediv').animate({'top': '+=500px', opacity: 0},function(){
$(this).hide();
});
});

Site loads on the right, then shifts to its actual position

There is a link at the bottom. Pretty much what happens, is when the page gets opened, it loads entirely on the right side of the screen. Then when it finishes loading every single element, it moves to the center which is it's actual position.
I believe the problem is caused by javascript, since the site works perfectly fine without it. It doesn't seem to matter what javascript is included, if I leave just 1 of them, the whole thing comes back.
Could really use the help. Also the site right now is about 500 pages big, so I'm really hoping for a solution which can fix this with just a few steps.
Thanks.
Here is the link to the page so you can get css/code: http://bit.ly/3EyoWu
Its definitely javascript. I think the banners on your site are loaded at the very end, which leaves the browser making incorrect guesses about the dimensions of the content until the page is loaded.
Try enclosing your javascript code inside fixed width (and height) divs or tables. You can easily determine the width (and height) required by javascript generated code by inspecting your page after its loaded. If its the banners, they are almost always predefined size.
Edit 1 ----
I got it. The specified cell widths for your table are narrower, the browser therefore is unable to calculate the page layout until the page is rendered completely. A column with width 110px has a banner having width = 120px.
Edit 2 ----
Try specifying widths for all-but-one column. That is, if you have three columns in the suspect table, specify the width for two, and let the browser decide the width for the third. Furthermore, the banners seem to occupy a width of 125px instead of 120px, probably because of unnecessary white space around them. I suggest that you revise the column widths appropriately (and parent table's width if necessary).
This might almost qualify as a 'flash of unstyled content' (FOUC) except that the browser doesn't first render a page in an unstyled format.
Instead, you see styled content before the Javascript is able to add the finishing touches.
You might get some further hints by searching for 'flash of unstyled content'.

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