Figuring out if overflow:auto would have been triggered on a div - javascript

// Major edit, sorry in bed with back pain, screwed up post
One of the ad agencies I code for had me set up an alternate scrolling solution because you know how designers hate things that just work but aren't beautiful.
The scrolling solution is applied to divs with overflow:hidden and uses jQuery's scrollTo(). It's a set of buttons top and bottom that handle moving the content.
So, this is married in places to their CMS. What I have not been able to sort yet is how to hide the scrolling UI when overflow:auto would not have been triggered by the CMS content and the buttons are not needed.
The divs have set heights and widths. Can i detect hidden content? Or measure the div contents' height?
Any ideas?

So you want to get the height of a hidden element? I found this post maybe it is what you are looking for.
Its using jQuery, but the concept is the same. Hope this helps!
Metropolis

I hope i am mistaken, but you would need to emulate overflow by setting properties using some js, then you can get these values using getAttribute or your own method. Otherwise when you set overflow to auto, then the browser will be doing its own thing and the only value returned as a property of overflow would be a string like 'auto'.

Can you explain this better? You want to hide the scrollbar of a div set to overflow:auto when it doesnt have enough text to overflow? Browser does this for you.
You want to hide the scrollbar of a div set to overflow auto when it is scrolled down to some point, but you arent looking at it or hovering or something? That will be sort of complicated.
If you want to know if a div has overflow set to something, you just do:
object.style.overflow
and it will give you a string.
possible values:
visible
hidden
scroll
auto
inherit
you can set overflow the same way
http://www.w3schools.com/css/pr_pos_overflow.asp
from what i understand now is you have these divs with hidden scroll, but some graphic designer custom scroll bar and you use scrollTo to do the actual scrolling. BUT you problem lies when you dont have enough data to actuall need a scrollbar, but your graphic stuff shows up anyway, so you want to hide it.
so the real question here is how do you get the height of content? you want the property offsetHeight, but im pretty sure its still IE only.

What do you mean by CMS?
Yes you can access the div's content height, since you can access all of the div's children in JavaScript. (Sorry for not including example. I haven't work with pure JS in a while now so I don't want to point you in the wrong direction.)
Doing this, you'll kind of be able to "detect hidden content" and then be able to do what you actually want to do.
About your first question, I doubt you can control scroll bars once you've set overflow to auto.

Using jQuery height() on a div containing the content I am able to show/hide the user interface as needed based on whether height exceeds the CSS height of the div with overflow:hidden.

Related

Skrollr. change content in fixed div

I wonder how to achieve this effect on http://www.squarespace.com. What I mean is:
you scroll down and at one point the image of computer monitor stays at fixed position
after that, the images keep changing while you scroll.
How can you control content and change CSS using Javascript? It should be on window scroll event:
window.onscroll = function () {
// but I don't know what to use here
}
At smaller browser width, the above elements become a carousel, but I am not interested in that.
Because of the tags on this post I'm going to assume that this question is regarding the skrollr library
Skrollr is controlled via HTML data attributes. What you're seeing when the monitor scrolls, and then becomes fixed at a given position, is referred to as "pinning". How you define data attributes in Skrollr can be pretty confusing at first, but once that is understood, the library is kind of a dream to work with.
I printed and pinned Petr Tichy's cheat sheet next to my monitor the first few weeks of my first skrollr project.
An example of pinning in Skroller would be accomplished as such:
<div id="example"
data-100-top="position:fixed;"
data-anchor-target="#example">
These words are pinned 100px from the top of the screen
</div>
The purpose of Skrollr is that knowledge of jQuery/JavaScript isn't really required. The css is manipulated by the library, and defied in the data elements. The above example shows changing the position to fixed, but if you wanted the div to expand 100px from the top you could input width/height css parameters in there, or just about any other css you'd like.
If you're looking for a more robust skrolling library, in which jQuery knowledge is more of a requirement, I recommend you take a look at ScrollMagic (my lack of reputation prevents me from linking to scrollmagic).

How to allow vertical scroll in absolute layout?

I'm working on this website right now http://antoniobrandao.com/v4
All objects are placed in absolute positions. Unfortunately this doesn't enable vertical scrolling.
I've read that using position:static in a parent element (in my case, the DIV sections-wrapper ) would do the trick, and yes a scrollbar appears, but the contents seem visually destroyed when I attempt to scroll after setting position: fixed to my sections-wrapper DIV.
I'm new to HTML5 so if anyone could give me a hint I would be most thankful!
thanks
I found out the answer to my own question.
The solution was to manually (via JavaScript) set the height of my "sections-wrapper" and "background" to match the height of the contents of the sections within the "sections-wrapper".
This is because the "sections-wrapper" doesn't know automagically how tall is the stuff within itself, so we must tell it ourselves. The downside is that we must always be updating this values when the contents change height within the wrapper. Not too bad.
so if the stuff within my wrapper is eg. 1200px:
$('.background').css('height', '1200px');
$('#sections-wrapper').css('height', '1200px');

Make a content visible when mouseover on 1/3 width of container without adding subcontainers

I have div container with width 100%. I need to make a content hide and show according to mouse over in container. But this will need to happen with 30% from left of main container and rest(70%) with no show/hide effect. Can we make this effect without adding any additional sub containers?
An Image representation
How to make this effect?
This Fiddle illustrates a very basic solution; it calls the effect every time the mouse moves inside the 30%, so you might need to add some further logic to prevent that happening.
I've used a container of 500px width, and a subcontainer div, but only for illustrative purposes; the JavaScript will manage a single container of any width. You'll need to add any positioning, margin or padding to the 'widthModifier' variable, but you could get those from the container in JavaScript too, if you wanted.
Daniel's answer doesn't solve the problem showing and hiding the content. Take a look at my solution that does exactly what you want. I used CSS features to achieve the result.
Use Chrome to view the example. For other browsers you just have to add their specific implementations of the css features.

hide lines of text not fully visible with javascript & css

I think this might be impossible, but is there some way using JQuery to prevent lines of text not fully visible from showing up on the screen when a user scrolls until the entire line is visible? That is, we want to prevent something like this from showing up:
Thanks!
I agree with #rahmanisback, don´t mess with the user's browsing experience.
However, what would perhaps be a nice "inbetween" solution, is using a transparency gradient so that the bottom pixels fade out. But that would apply also to "whole" lines, so perhaps that´s not a good solution for your problem.
I don't know if there is something out there to do that. But I think it will cause confusion more that it would make any visual enhancement ever. A user will not be happy when scrolling down and finds lines just "popup" suddenly, in opposite to normally easing out as a result of scrolling action.
After all, when we speak about a scrollable HTML element with scrollbars visible, a user is aware text might be partially shown and that is normal and needs to be scrolled down to read the remaining. I really would not recommend that.
But for a technical answer, I think you would need to fix the CSS line-height property of that scrolling element, say make it 8px or whatever fits your layout. Then, capture the scroll event and devide the jQuery scrollTop() by that CSS line-height, then check the results: if it have a fraction then that means there is a "partially visible" line. Don't forget aout margin and padding that can cause mistakes when calculating.
I believe I have had this problem also, in that you have a div with a specific height and overflow hidden.
Thinking about it i would resize the div based on the line-height of the text in the div.
Change the height of div so that it equals a multiple of the line height of the containing text....
ie 3 lines of text with line-height = 16 change the div height from 50 to 48px.
( i posted this at the same time as rahmanisback' answer )
Hypothetically you could measure the height of text area, measure the height of the line, find scroll position do some math and then have some way of hiding text that is not fully exposed yet (eg Using a white div of x height depending on your math). However, it seems like a lot of trouble to go to for something that is usually a non-issue. You might also be able to do something with the overflow property, but you might have some issues with that I'm not sure.
I thought of an alternate method that would be easier to implement. Capture scroll events and then change it to the closest multiple of line height.

I need horizontal scrolling for GridView

I've got my GridView inside another Panel and I got scrollbars but GridView is to big even with paging. So user needs to scroll down to scroll horizontal (to see horizontal scrollbar).
How can I add any horizontal scrolling trick for my GridView in the Panel. Maybe something from javascript ? My js knowledges is still being poor.
I really hard thinking on what that could be, maybe floating horizontal scrollbar ?
Thank you.
This can be done with the CSS Overflow property, see: http://www.w3schools.com/Css/pr_pos_overflow.asp
You may be able to add this to your asp Control, or see how the <asp:Panel> is rendered (I haven't used WebForms for a while, but I think it's a HTML <span>) and give it an appropriate element Id/class and set the CSS property in a seperate stylesheet.
I think this is what you are searching for? :
scrollLeft

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