I've got a container div with a bunch of scrollable content (for the record I'm using iScroll - if that changes the solution). When I scroll to the top I want to load content above the current scroll position. If I simply prepend the div using jQuery "prepend();" the contents in my scrollable area shift down. Ideally we'd want to keep the current content in the frame and have the scrollable area grow upwards above the content.
Any thoughts?
Thanks!
According to the iScroll website, it has a method called scrollToElement:
scrollToElement(el, runtime): scrolls to any element inside the scrolling area. el must be a CSS3 selector. Eg: scrollToElement("#elementID", '400ms')
If you always prepend a fixed amount of divs (e.g. always a single div), I imagine you could use it to scroll to (e.g.) the second element right after you've prepended the new content:
// ... (prepend new content)
myScroll.scrollToElement('#scroller :nth-child(2)', '0ms');
I haven't tried this, so please let us know if this works for you.
After a quick look through iScroll's source, here's what I've found:
The current x and y are always available through myScroll.x and myScroll.y.
iScroll has an internal function _offset(el), which returns the left and top offset of any given element.
This basically opens up two solutions:
Use _offset(el). While possible, this is inadvisable. The underscore is a convention for marking a function "private", meaning, amongst other things, that it's not part of the official API.
or
Use the newly added element's height:
var x = myScroll.x;
var y = myScroll.y;
// ... (prepend new content)
y += $('#scroller :first-child').outerHeight();
myScroll.scrollTo(x, y, '0ms');
You may need to pass true to .outerHeight(), which makes it include margins.
Once again, I haven't tested this, so please let us know if it works.
Related
Right now I have a web page with:
A fixed header at the top of varying size, covering up the page's main content.
A page with a deeply nested scroll container.
Within that container, several other deeply nested elements.
What I want to do is scroll that container so that one of the elements inside lines up with the top of the visible portion of the container. I believe what I am looking for is the top of the nested element relative to the top of the visible portion of the container.
Unfortunately I cannot use .offsetTop because that only references an element's immediate parent, and due to the structure of the page these elements are too deeply nested for that to be of any use. It's always a fixed number. Same with the scroll container; its immediate parent is not the window. Frustratingly, the header is not of a fixed height, so I can't hardcode it into my calculations very easily. I also cannot use jQuery.
I tried using getBoundingClientRect for both the element and the container, but they are always a fixed distance away from each other and it doesn't give me the information I need about how far the element is scrolled relative to the container's visible area, unfortunately.
EDIT: We have a scrolling solution in place already, but we were hoping to improve it through a certain proposed means that I am trying to determine the feasibility of. I would like to ask that everyone please try to only answer the question in bold, rather than proposing alternate solutions. I really do appreciate any help on offer, but I am hoping to get some extremely specific information based on an extremely specific scenario.
I also had this kind of issue earlier, you can try this to auto scroll to the element
var elem = <some select operation that returns the element>;
elem.id = <some temp id> //if no id is there
var a = document.createElement('a');
a.href = "#" + elem.id;
a.click();
If you wish, you can remove the id from your element once its done.
I am using pure Polymer/Javascript and need to scroll to the bottom of my main panel. Since it is a scrollable element within a fixed-size container the typical JS answer
window.scrollTo(0,document.body.scrollHeight);
Does not work.
Couldn't find a direct solution so posting an the answer myself. Hope this helps someone :)
(Based on what I found here)
//Get the main paper-drawer-panel element
a = document.querySelector("paper-drawer-panel [main]")
//use the undocumented scroller property and set it to the scroller's height
a.scroller.scrollTop = a.scroller.scrollHeight
UPDATE:
I also discovered that if you select any element or container within the panel there should be scrolling methods attached to them allowing you to to scroll to the top or bottom of the panel based on the selected element.
//Get the main paper-drawer-panel element
a = document.querySelector("some-element-container-in-paper-panel");
// Passing in false scrolls to the bottom of the container, no param to the top.
a.scrollIntoView(false)
I may not comment (I need 50 points of something) but scrollIntoView() is experimental technology. Not supported by Chrome.
Ok, the subject is not super specific to the overall need I am looking to address. So I have this function that is called on a given element, which is a hidden submenu next to a triggering element. The way the page renders, and to keep the styling optimized I can't just style the position in via css. So I need javascript/jquerys help.
With that I have come up with a function that I can reuse as needed, and works fine all around. However my key problem is, that I have a couple cases where the submenu will overlap the edge of the <section> element it resides in. Which that elements overflow is set to hidden, that and its also about 30 pixels from the bottom of the page anyway. All in all the submenu element gets hidden a bit by either falling completely out of the pages view half way through the element, or it gets hidden by the section tags overflow state.
With that. In a case where this happens I am wanting to instead of have the element align to the bottom of the trigger element, have it align to the top instead so that way the menu in that case is above the trigger element and not below.
Problem is Im not sure how to compensate for that.
Here is the function I came up with to do what I need, now I just need some help in a sense catching when the menu element falls off the page so to speak, so I can adjust for it when it does.
function openSubOrgMenu(triggerID, elem)
{
orgSubOpenID = triggerID;
orgSubShowing = true;
elemOffset = elem.offset(); //trigger element
elemWidth = elem.width();
elemHeight = elem.height();
elemWrap = elem.siblings('.org_group_wrapper');//menu element
elemWrapWidth = elemWrap.width();
elemWrapHeight = elemWrap.height();
moveTop = elemHeight + elemOffset.top + 4;
moveLeft = elemOffset.left - (elemWrapWidth-elemWidth-15);
elemWrap.show().offset({top:moveTop, left:moveLeft});
}
Well here is a JS Fiddle, not necessarily showing a working logic of what I want, but demonstrating the desired effect when its an element that at the bottom of the page/section:
http://jsfiddle.net/4zwEr/
Any idea how make a layout like google plus or facebook. You can see at google plus home as example,
at the beginning, if you scroll the page in the main content, they will scroll together (friend post and sidebar), but when you scroll until the bottom of sidebar (in the right of friend post), that sidebar will stop scrolling , but the another content (friend post) will still scrolling. can explain to me how to make layout like that? sample code or demo will be very help.
Fixed positioning with CSS is a very limited approach. There are a number of ways to do this style of "fixed" areas, many of which have already been given in answers to similar questions on here (try the search above?).
One technique (which many are based on) is like so (in brief)..
Capture the browser's scrolling
Get the position from top of chosen element (x)
Check if the scrolling > x, if so apply a class to the element to fix it to a certain position.
The same will work in reverse, for example:
var target = $('#div-to-stick');
var div_position = target.offset().top;
$(window).scroll(function() {
var y_position = $(window).scrollTop();
if(y_position > div_position) {
target.addClass('fixed');
}
else {
target.removeClass('fixed');
}
}
Note: Depending on how you chose to complete the code above, the page will often "jump" as the div's position is modified. This is not always a (noticeable) problem, but you can consider getting around this by using .before with target.height() and appending a "fake" replacement div with the same height.
Hope this helps.
The new approach with css3 is reduce your effort. use single property to get it.
position:sticky;
here is a article explained it and demo.
article
Demo
You are looking for CSS position:fixed (for the scroll-along sidebar), you can set the location with left:[length], right:[length], top:[length], bottom:[length] and the normal width and height combos
You will need to augment it with a window resize and scroll listener that applies the position:fixed property after the window has scrolled past the top of the sidebar.
Use css property (position:fixed). This will keep the position of the div fixed even if you scroll down or scroll up.
I've got a div that uses overflow:auto to keep the contents inside the div as it is resized and dragged around the page. I'm using some ajax to retrieve lines of text from the server, then append them to the end of the div, so the content is growing downwards. Every time this happens, I'd like to use JS to scroll the div to the bottom so the most recently added content is visible, similar to the way a chat room or command line console would work.
So far I've been using this snippet to do it (I'm also using jQuery, hence the $() function):
$("#thediv").scrollTop = $("#thediv").scrollHeight;
However it's been giving me inconsistent results. Sometimes it works, sometimes not, and it completely ceases to work if the user ever resizes the div or moves the scroll bar manually.
The target browser is Firefox 3, and it's being deployed in a controlled environment so it doesn't need to work in IE at all.
Any ideas guys? This one's got me stumped. Thanks!
scrollHeight should be the total height of content. scrollTop specifies the pixel offset into that content to be displayed at the top of the element's client area.
So you really want (still using jQuery):
$("#thediv").each( function()
{
// certain browsers have a bug such that scrollHeight is too small
// when content does not fill the client area of the element
var scrollHeight = Math.max(this.scrollHeight, this.clientHeight);
this.scrollTop = scrollHeight - this.clientHeight;
});
...which will set the scroll offset to the last clientHeight worth of content.
scrollIntoView
The scrollIntoView method scrolls the element into view.
Using a loop to iterate over a jQuery of one element is quite inefficient. When selecting an ID, you can just retrieve the first and unique element of the jQuery using get() or the [] notation.
var div = $("#thediv")[0];
// certain browsers have a bug such that scrollHeight is too small
// when content does not fill the client area of the element
var scrollHeight = Math.max(div.scrollHeight, div.clientHeight);
div.scrollTop = scrollHeight - div.clientHeight;
$("#thediv").scrollTop($("#thediv")[0].scrollHeight);
It can be done in plain JS. The trick is to set scrollTop to a value equal or greater than the total height of the element (scrollHeight):
const theDiv = document.querySelector('#thediv');
theDiv.scrollTop = Math.pow(10, 10);
From MDN:
If set to a value greater than the maximum available for the element,
scrollTop settles itself to the maximum value.
While the value of Math.pow(10, 10) did the trick using a too high value like Infintiy or Number.MAX_VALUE will reset scrollTop to 0 (Firefox 66).
I had a div wrapping 3 divs that were floating left, and whose contents were being resized. It helps to turn funky-colored borders/background on for the div-wrapper when you try to resolve this. The problem was that the resized div-content was overflowing outside the div-wrapper (and bled to underneath the area of content below the wrapper).
Resolved by using #Shog9's answer above. As applied to my situation, this was the HTML layout:
<div id="div-wrapper">
<div class="left-div"></div>
<div id="div-content" class="middle-div">
Some short/sweet content that will be elongated by Jquery.
</div>
<div class="right-div"></div>
</div>
This was the my jQuery to resize the div-wrapper:
<script>
$("#div-content").text("a very long string of text that will overflow beyond the width/height of the div-content");
//now I need to resize the div...
var contentHeight = $('#div-content').prop('scrollHeight')
$("#div-wrapper").height(contentHeight);
</script>
To note, $('#div-content').prop('scrollHeight') produces the height that the wrapper needs to resize to. Also I am unaware of any other way to obtain the scrollHeight an actual jQuery function; Neither of $('#div-content').scrollTop() and $('#div-content').height would produce the real content-height values. Hope this helps someone out there!