link to anchor near bottom of page - html

I'm doing some documentation where I make heavy use of anchors for linking between pages on a wiki.
see here:
http://code.google.com/p/xcmetadataservicestoolkit/wiki/ServicesExplained#Platform_Data_Structures
The feature that really makes this work well is when the browser shows the anchor at the absolute top of the pane. When it gets confusing is when linking to an anchor shows the anchor half-way down the page since the page is scrolled down all the way
see here:
http://code.google.com/p/xcmetadataservicestoolkit/source/browse/trunk/mst-common/src/java/xc/mst/utils/Util.java#227
My solution in the wiki (first link) was to put a blank image at the bottom of the page simply to make the browser show the anchor right at the top. Is there a better way to do this? Is there a way to do it in the second link (in which I can't add a blank image)?

Putting a blank image at the bottom of your page is a bad idea, since it will expand your document to a unnecessary height.
You could throw in some javascript to apply an effect to the anchor you just travelled to, to highlight it wherever it is.

Without altering the height of your document (i.e. adding extra padding at bottom), you'll always have this issue.
However, using bit of JS/jQuery, the user experience can be improved considerably:
On clicking a named anchor:
Instead of jumping in a flash (broswer's default behavior), add a smooth scroll
add an highlight to indicate current selection (this helps tremendously in 2nd case as the user can clearly see what is current)
Created a demo to illustrate the concepts: http://jsfiddle.net/mrchief/PYsyN/9/
CSS
<style>
.current { font-weight: bold; }
</style>
JS
function smoothScroll(elemId) {
// remove existing highlights
$('.current').css({backgroundColor: "transparent"}).removeClass('current');
var top = $(elemId).offset().top;
// do a smooth scroll
$('html, body').animate({scrollTop:top}, 500, function(){
// add an highlight
$(elemId).animate({backgroundColor: "#68BFEF" }, 500, function () {
// keep tab of current so that style can be reset later
$(elemId).addClass('current');
});
});
}
// when landing directly
if (document.location.hash) {
smoothScroll(document.location.hash);
}
$('a[href*="#"]').click(function() {
// utilizing the fact that named anchor has a corresponding id element
var elemId = $(this).attr('href');
smoothScroll(elemId);
});

You can create a absolutre positioned pseudo-element with a great height to targeted block using just the following CSS (for the second link in your post:
#nums td:target a::before {
content: '';
position: absolute;
height: 700px;
}
The height must be around the height of the viewport, so the best solution is to create these styles on the fly using js. But if you don't wan't to use js, just use height: 1000px or more — if you don't mind a gap at the bottom of course.
The best part: it's only CSS and there would be no gap when no anchors are targeted.
Edit: just a sneak peek into the future: if the vw/vh units would come to other browsers (now it's only in IE9), this could be awesomely done with just CSS using height: 100vh :)

You could use Javascript / jQuery to create a white div that has the necessary height needed to put your element at the top of the browser window, and you could even remove this upon scrolling away.
However I would highly recommend against doing so as this will expand your page where it isn't needed. It's a lot smarter to simply style the tag upon going there (through Javascript / jQuery) so it pops out to the viewer, for instance by setting the font-weight to bold or changing the background-color.

I would probably use a combination of jQuery and PHP for this:
PHP(somewhere right after your <body> element):
<?php
$anchor = explode('#', $_SERVER['REQUEST_URI']);
$anchor = $anchor[1];
echo '<div id="selected-anchor" anchor="'.$anchor.'"></div>';
?>
And then the jQuery:
<script type="text/javascript">
$(function(){
$('#selected-anchor').css('background-color', '[Whatever highlight color you want]');
});
</script>
Hope this helps.

Related

Position SVG lines over HTML elements, while still allowing interaction with the HTMl elements [duplicate]

I have a div that has background:transparent, along with border. Underneath this div, I have more elements.
Currently, I'm able to click the underlying elements when I click outside of the overlay div. However, I'm unable to click the underlying elements when clicking directly on the overlay div.
I want to be able to click through this div so that I can click on the underlying elements.
Yes, you CAN do this.
Using pointer-events: none along with CSS conditional statements for IE11 (does not work in IE10 or below), you can get a cross browser compatible solution for this problem.
Using AlphaImageLoader, you can even put transparent .PNG/.GIFs in the overlay div and have clicks flow through to elements underneath.
CSS:
pointer-events: none;
background: url('your_transparent.png');
IE11 conditional:
filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(src='your_transparent.png', sizingMethod='scale');
background: none !important;
Here is a basic example page with all the code.
Yes, you CAN force overlapping layers to pass through (ignore) click events.
PLUS you CAN have specific children excluded from this behavior...
You can do this, using pointer-events
pointer-events influences the reaction to click-, tap-, scroll- und hover events.
In a layer that should ignore / pass-through mentioned events you set
pointer-events: none;
Children of that unresponsive layer that need to react mouse / tap events again need:
pointer-events: auto;
That second part is very helpful if you work with multiple overlapping div layers (probably some parents being transparent), where you need to be able to click on child elements and only that child elements.
Example usage:
.parent {
pointer-events:none;
}
.child {
pointer-events:auto;
}
<div class="parent">
I'm unresponsive
I'm clickable again, wohoo !
</div>
Allowing the user to click through a div to the underlying element depends on the browser. All modern browsers, including Firefox, Chrome, Safari, and Opera, understand pointer-events:none.
For IE, it depends on the background. If the background is transparent, clickthrough works without you needing to do anything. On the other hand, for something like background:white; opacity:0; filter:Alpha(opacity=0);, IE needs manual event forwarding.
See a JSFiddle test and CanIUse pointer events.
I'm adding this answer because I didn’t see it here in full. I was able to do this using elementFromPoint. So basically:
attach a click to the div you want to be clicked through
hide it
determine what element the pointer is on
fire the click on the element there.
var range-selector= $("")
.css("position", "absolute").addClass("range-selector")
.appendTo("")
.click(function(e) {
_range-selector.hide();
$(document.elementFromPoint(e.clientX,e.clientY)).trigger("click");
});
In my case the overlaying div is absolutely positioned—I am not sure if this makes a difference. This works on IE8/9, Safari Chrome and Firefox at least.
Hide overlaying the element
Determine cursor coordinates
Get element on those coordinates
Trigger click on element
Show overlaying element again
$('#elementontop').click(e => {
$('#elementontop').hide();
$(document.elementFromPoint(e.clientX, e.clientY)).trigger("click");
$('#elementontop').show();
});
I needed to do this and decided to take this route:
$('.overlay').click(function(e){
var left = $(window).scrollLeft();
var top = $(window).scrollTop();
//hide the overlay for now so the document can find the underlying elements
$(this).css('display','none');
//use the current scroll position to deduct from the click position
$(document.elementFromPoint(e.pageX-left, e.pageY-top)).click();
//show the overlay again
$(this).css('display','block');
});
I currently work with canvas speech balloons. But because the balloon with the pointer is wrapped in a div, some links under it aren't click able anymore. I cant use extjs in this case.
See basic example for my speech balloon tutorial requires HTML5
So I decided to collect all link coordinates from inside the balloons in an array.
var clickarray=[];
function getcoo(thatdiv){
thatdiv.find(".link").each(function(){
var offset=$(this).offset();
clickarray.unshift([(offset.left),
(offset.top),
(offset.left+$(this).width()),
(offset.top+$(this).height()),
($(this).attr('name')),
1]);
});
}
I call this function on each (new) balloon. It grabs the coordinates of the left/top and right/down corners of a link.class - additionally the name attribute for what to do if someone clicks in that coordinates and I loved to set a 1 which means that it wasn't clicked jet. And unshift this array to the clickarray. You could use push too.
To work with that array:
$("body").click(function(event){
event.preventDefault();//if it is a a-tag
var x=event.pageX;
var y=event.pageY;
var job="";
for(var i in clickarray){
if(x>=clickarray[i][0] && x<=clickarray[i][2] && y>=clickarray[i][1] && y<=clickarray[i][3] && clickarray[i][5]==1){
job=clickarray[i][4];
clickarray[i][5]=0;//set to allready clicked
break;
}
}
if(job.length>0){
// --do some thing with the job --
}
});
This function proofs the coordinates of a body click event or whether it was already clicked and returns the name attribute. I think it is not necessary to go deeper, but you see it is not that complicate.
Hope in was enlish...
Another idea to try (situationally) would be to:
Put the content you want in a div;
Put the non-clicking overlay over the entire page with a z-index higher,
make another cropped copy of the original div
overlay and abs position the copy div in the same place as the original content you want to be clickable with an even higher z-index?
Any thoughts?
I think the event.stopPropagation(); should be mentioned here as well. Add this to the Click function of your button.
Prevents the event from bubbling up the DOM tree, preventing any parent handlers from being notified of the event.
Just wrap a tag around all the HTML extract, for example
<a href="/categories/1">
<img alt="test1" class="img-responsive" src="/assets/photo.jpg" />
<div class="caption bg-orange">
<h2>
test1
</h2>
</div>
</a>
in my example my caption class has hover effects, that with pointer-events:none; you just will lose
wrapping the content will keep your hover effects and you can click in all the picture, div included, regards!
An easier way would be to inline the transparent background image using Data URIs as follows:
.click-through {
pointer-events: none;
background: url(data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7);
}
I think that you can consider changing your markup. If I am not wrong, you'd like to put an invisible layer above the document and your invisible markup may be preceding your document image (is this correct?).
Instead, I propose that you put the invisible right after the document image but changing the position to absolute.
Notice that you need a parent element to have position: relative and then you will be able to use this idea. Otherwise your absolute layer will be placed just in the top left corner.
An absolute position element is positioned relative to the first parent
element that has a position other than static.
If no such element is found, the containing block is html
Hope this helps. See here for more information about CSS positioning.
You can place an AP overlay like...
#overlay {
position: absolute;
top: -79px;
left: -60px;
height: 80px;
width: 380px;
z-index: 2;
background: url(fake.gif);
}
<div id="overlay"></div>
just put it over where you dont want ie cliked. Works in all.
This is not a precise answer for the question but may help in finding a workaround for it.
I had an image I was hiding on page load and displaying when waiting on an AJAX call then hiding again however...
I found the only way to display my image when loading the page then make it disappear and be able to click things where the image was located before hiding it was to put the image into a DIV, make the size of the DIV 10x10 pixels or small enough to prevent it causing an issue then hiding the containing div. This allowed the image to overflow the div while visible and when the div was hidden, only the divs area was affected by inability to click objects beneath and not the whole size of the image the DIV contained and was displaying.
I tried all the methods to hide the image including CSS display=none/block, opacity=0, hiding the image with hidden=true. All of them resulted in my image being hidden but the area where it was displayed to act like there was a cover over the stuff underneath so clicks and so on wouldn't act on the underlying objects. Once the image was inside a tiny DIV and I hid the tiny DIV, the entire area occupied by the image was clear and only the tiny area under the DIV I hid was affected but as I made it small enough (10x10 pixels), the issue was fixed (sort of).
I found this to be a dirty workaround for what should be a simple issue but I was not able to find any way to hide the object in its native format without a container. My object was in the form of etc. If anyone has a better way, please let me know.
I couldn't always use pointer-events: none in my scenario, because I wanted both the overlay and the underlying element(s) to be clickable / selectable.
The DOM structure looked like this:
<div id="outerElement">
<div id="canvas-wrapper">
<canvas id="overlay"></canvas>
</div>
<!-- Omitted: element(s) behind canvas that should still be selectable -->
</div>
(The outerElement, canvas-wrapper and canvas elements have the same size.)
To make the elements behind the canvas act normally (e.g. selectable, editable), I used the following code:
canvasWrapper.style.pointerEvents = 'none';
outerElement.addEventListener('mousedown', event => {
const clickedOnElementInCanvas = yourCheck // TODO: check if the event *would* click a canvas element.
if (!clickedOnElementInCanvas) {
// if necessary, add logic to deselect your canvas elements ...
wrapper.style.pointerEvents = 'none';
return true;
}
// Check if we emitted the event ourselves (avoid endless loop)
if (event.isTrusted) {
// Manually forward element to the canvas
const mouseEvent = new MouseEvent(event.type, event);
canvas.dispatchEvent(mouseEvent);
mouseEvent.stopPropagation();
}
return true;
});
Some canvas objects also came with input fields, so I had to allow keyboard events, too.
To do this, I had to update the pointerEvents property based on whether a canvas input field was currently focused or not:
onCanvasModified(canvas, () => {
const inputFieldInCanvasActive = // TODO: Check if an input field of the canvas is active.
wrapper.style.pointerEvents = inputFieldInCanvasActive ? 'auto' : 'none';
});
it doesn't work that way. the work around is to manually check the coordinates of the mouse click against the area occupied by each element.
area occupied by an element can found found by 1. getting the location of the element with respect to the top left of the page, and 2. the width and the height. a library like jQuery makes this pretty simple, although it can be done in plain js. adding an event handler for mousemove on the document object will provide continuous updates of the mouse position from the top and left of the page. deciding if the mouse is over any given object consists of checking if the mouse position is between the left, right, top and bottom edges of an element.
Nope, you can't click ‘through’ an element. You can get the co-ordinates of the click and try to work out what element was underneath the clicked element, but this is really tedious for browsers that don't have document.elementFromPoint. Then you still have to emulate the default action of clicking, which isn't necessarily trivial depending on what elements you have under there.
Since you've got a fully-transparent window area, you'll probably be better off implementing it as separate border elements around the outside, leaving the centre area free of obstruction so you can really just click straight through.

can't use css on .scroll-content because it breaks ion-infinite-scroll

The first image below shows the unwanted whitespace that is being created by an excessively large margin-top on .scroll-content. I countered this by putting margin-top: -47% on .scroll-content. However, doing this broke my ion-infinite-scroll on the page. It seems that any and all css that I put on .scroll-content breaks ion-infinite-scroll.
If you click on the images to look closer. You can see in the devtools Elements section that the margin-top is being created dynamically somewhere as it is added as an inline style. Does anyone know any tricks for how to either move the whole .scroll-content up or how to negate the margin-top? I don't really have any css to show for this...I am just trying to override an element's style that is created by ionic. Again, any css that I use on .scroll-content breaks ion-infinite-scroll so this needs to be done in a really hacky way (yay css).
Also, changing it dynamically with setElementStyle or something like setAttribute('style', 'margin-top: 132px') breaks .ion-infinite-scroll.
As a workaround I made my own bottom-of-the-screen-when-scrolling detector:
let element = this.elRef.nativeElement.querySelector('.scroll-content');
element.addEventListener('scroll', (event) =>
{
var element = event.target;
if (element.scrollHeight - element.scrollTop === element.clientHeight)
{
... loading new items code goes here ...

Active state and display:none causes link not to work

Consider the following fiddle: http://jsfiddle.net/GMA76/
On the links active state I want to replace the content of the a tag, then it should continue to follow the link. However when I style it as shown in the fiddle and here:
a div:first-child{
display:block;
}
a div:last-child{
display:none;
}
a:active div:first-child{
display:none;
}
a:active div:last-child{
display:block;
}
The link doesn't work the first time you click it. It only replaces the content and then it seems the redirection fails.
How would I fix that?
Browsers don't take well to content changing on the :active event. Even if it did work, a CSS-only solution would likely mean that the user wouldn't even see the change in content before the new page had loaded (or started to load with a white screen). I tested a lot with the :after pseudo-selector and the content property, but this didn't work either.
And rightly so. Changes to content should only be done with a language like Javascript. This is a logic issue and is outside of the scope of a styling language. Therefore, I would suggest using Javascript.
I've created a quick fiddle here using Javascript with jQuery (doesn't need jQuery it but it's easier) to switch the text in the link and then go to the new page exactly 1 second afterwards. This way you only need to have the original link in the HTML rather than hiding separate links with CSS. There are more flexible and extensible ways to do this if it's not just for one or two links but for the sake of an example, take a look at the fiddle.
This is the jQuery:
$(".switch-link").click(function(){
$(this).text("Test Two");
var href = $(this).attr('href');
setTimeout(function(){
window.location = href
}, 1000);
return false;
});
1000 is the delay between the text changing and the browser starting to load the new page, you can change this to suit your needs.

Always visible div while scrolling

On my aspx page, I have two left and right portions. I want to show always left side (which is actually a 'div' containig treeview) while scrolling the right side (which are actual contents of page). Thanks
You need to put position: fixed; on the div element. That will anchor it to the viewport.
Hi I found the best solution! As always JQUERY saving my life !!
Just put a Div called as you wan, I've chosen the same in the example below: #scrollingDiv.
<script type="text/javascript" src="jquery-1.3.2.min.js"></script>
<script>
$().ready(function() {
var $scrollingDiv = $("#scrollingDiv");
$(window).scroll(function(){
$scrollingDiv
.stop()
.animate({"marginTop": ($(window).scrollTop() )}, "slow" );
});
});
</script>
I took that code from a website, it works and it's pretty easy to understand.
Fast forward to 2020, and it is now possible to do this with CSS.
<div style="position: sticky; top: 0;"> Tree view </div>
The user npas explains this quite nicely:
top is the distance to the viewport top the div should stay at when you scroll. Specifying top is mandatory. (…)
The sticky div will act like a normal div in all ways except when you scroll past it, then it will stick to the top of the browser.
Here's a jsfiddle to give you an idea.
MDN documentation
Supported by all modern browsers
You need to set the position of the div to Fixed in CSS. See this link for more information. You will need to set position using the top and left in css as well so it knows where to fix it!
The problem is that when the block moves, it gets attention and ability to concentrate on reading.
To remedy this using this function.
This code is perfect :
(change "220" and "46px" if necessary)
var $scrollingDiv = $("#scrollingDiv");
$(window).scroll(function(){
if ($(window).scrollTop()>220) {
$scrollingDiv
.css("position",'fixed' )
.css("top",'46px' )
} else {
$scrollingDiv
.css("position",'' )
.css("top",'' )
}
});

Fixed header inside scrolling block

I'm trying to create a block which may or may not have a scrollbar, with a header that does not scroll. The trick is that the width of the header should be affected by the presence of a scrollbar.
I'm worried that this is one of those CSS use cases which should be trivial, but might, in fact, be impossible. Anyone willing to prove me wrong?
Here are a few pointers
http://davidchambersdesign.com/css-fixed-position-headers/
and there involve tables with fixed header and scrolling body
http://imar.spaanjaars.com/357/a-scrollable-table-with-a-fixed-header
http://anaturb.net/csstips/sheader.htm
You cannot do this with CSS alone. We must use javaScript. With jQuery you can do the following
var cw = $('#container').innerWidth(),
cs = $('#container').scrollTop();
$('#header').css({
'width': cw + "px"
});
$('#container').scroll(function() {
$('#header').css({
'top': $('#container').scrollTop(),
})
})
Check working example at http://jsfiddle.net/VswxL/2/
I haven't figured out how to do this with CSS alone. So, here's a solution which uses JavaScript (here, jQuery), but only runs when he content changes. If the size of your wrapper depends on the size of the window, you may also need to run it on resize. Here's the heart of it:
$.fn.fitTo = function(target){
var $el = $(this);
$(target).bind('refit', function(){
$el.width(this.clientWidth);
});
}
Call $header.fitTo($content) to bind the header to a custom refit event on the element with the content. Now, whenever the content changes such that a scroll bar may have appeared or disappeared, do…
$content.trigger('refit');
…and the width of the header is reset to the clientWidth of the element containing content. The header must be outside the scrolling element.
Working example