Apply gradient over page without hindering user interaction [duplicate] - javascript

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.

Related

Javascript: Child should not be inheriting mouse state from Parent

I'm trying to create a small image that follows the mouse around but only exists inside a specific area. I'm using javascript/jquery to create the image when the mouse enters the area and remove it when the mouse leaves.
The problem is, if I create the "follower" inside the area div, the image seems to be considered part of it's parent for determining mouse state, and thus it continues to exist even after the mouse is outside the area.
(If I move the mouse fast enough the cursor will escape and the follower disapears.)
Here is the code I'm using:
$("#area").mouseenter(function() {
$("#area").append("<img id='follower' src='follower.png'/>");
});
$("#area").mousemove(function(event){
$("#follower").css("top",event.pageY-35);
$("#follower").css("left",event.pageX-35);
});
$("#area").mouseleave(function() {
$("#follower").remove();
});
JSFiddle: http://jsfiddle.net/cgWdF/186/
I have also attempted creating the "follower" inside a separate div, which works but results in a weird flickering of the image, as seen here: http://jsfiddle.net/cgWdF/187/
Any help, with this, would be appreciated. It doesn't matter whether the follower is created inside the area div, or not, as long as the flickering affect isn't seen. Also, I'd like to keep the code as compact as possible, but I'll take what I can get.
This occurs because the element on which you mouseleave is not the one on which you think it happens. In fact, your sprite is triggering the event instead because your pointer is over it at that time.
To prevent that from happening, you can force the page to cancel all pointer events on your sprite. By doing that, #area will trigger your pointer events as intended. The css rule pointer-events might be helpful for this.
CSS
#follower {
position: absolute;
height: 80px;
pointer-events: none;
}
There are probably better ways to deal with that but it's the most simple I can come up with for now.
Hope this helps!
See FIDDLE.

click events and css attributes not attaching to divs, possibly because divs are "mostly padding"

I'm trying to attach click events to a couple of divs. One of which has no height or width, just borders. Maybe it's just the browser, but the clicks are being triggered very unreliably. Even the css parameters .class:hover{} isn't really working.
$("body").on("click", "._tlh_dropdown, ._tlh_dropdown *", function (event) {
isn't working when the a div contained by ._tlh_dropdown is clicked. And the div ._tlh_dropdown_close_button is not removing it's parent div when clicked, nor turning a darker shade of gray when it is hovered over. What am I doing wrong here? I assume it has to do with the click event not being applied to the areas of the divs that are "just padding". Is this the case? How can I overcome this?
http://jsfiddle.net/UrNUM/7/
This is happening because the underline element that is a div element overlaps the elements in question . As you know div is a block level element.
One work around is to to set the 2 divs to inline-block
._tlh_dropdown_input_container, ._tlh_dropdown{
display: inline-block;
}
Check Fiddle for hover
If you want the div to be block level as it is then you can also play around with the z-index
._tlh_dropdown_close_button{
z-index: 1;
}
This will make sure the close div is always on top of the underlying container
UPDATE
2 events fire for every click event on the page..
So the content is not shown when u click on the image because of this condition
if ($targ.hasClass('_tlh_dropdown')
|| $targ.closest('._tlh_dropdown_content').length)
return;
This happens because the e.target when you click on the arrow image will be the arrow and not the tlh_dropdown .. So it fails on this condition and moves to the next statement where the content is removed.
Change it
if ($targ.hasClass('_tlh_dropdown')
|| $targ.closest('._tlh_dropdown').length
|| $targ.closest('._tlh_dropdown_content').length)
return;
It should work..
Check Fiddle
Also I feel the same can be accomplished with a lot less code. You can always have the HTML already built and then hide or show based on the condition.
Regarding the close button, if you hover "_tlh_dropdown_input_container" in the inspector, you can see that it overlaps the bottom part of the X button. That's why the hover/click event on the X is not caught below the middle of it.
Regarding the down arrow, just wrap it with another DIV on which you'll add the events. You can achieve minimal HTML by using a single DIV and adding the arrow to it using CSS :before or :after.

selecting an element on mouse click overlapped by another transparent div

I am working on a dashboard where user can drag and drop elements to create html pages.Now,he can have multiple images using an image component.We have managed to calculate the z-index of the images and they can be adjusted using up-down keys.
Issue:
The issue we are facing is when we select a image component we attach a dotted layer above it for helping the user to easily drag and resize it.If the user places the images as shown in the image below
we are not able to select the inner image again because the z-index of the selection div(the one with the blue dots) is(has to be) the highest(highest bcoz we have to use it for all components).So if I try to select the inner image now it cannot be selected.How can I handle the situation? For reference it works on this site as expected.
I believe we have get the element under the parent when it is clicked.But not sure how!We are using javascript,jquery to handle the events.
You can use JavaScript or jQuery to get the position of the inner image, and when the user clicks on the outer image, check to see whether the mouse position lies within the range of the smaller image. The range can be calculated with the position, width, and height of the inner element.
To get the element's position: use jQuery .offset() or .position() (The former is relative to the document, the latter to the parent).
To get the mouse position: http://docs.jquery.com/Tutorials:Mouse_Position
You could consider hiding the masking element quickly in order to gather the coordinate for your underlying element, when done, you could re enable visibility for the masking element. Use document.elementFromPoint() in order to get the DOM item from mouse coordinate.
An example:
http://jsfiddle.net/s94cnckm/14/
Alternatively you can use The CSS property pointer-events: none; on the masking element.
Related:
https://developer.mozilla.org/de/docs/Web/CSS/pointer-events
How to detecting a click under an overlapping element?

How to respond to a click outside a certain area?

My document looks like this:
Basically the background is one full-screen, transparent div. There are couple problems...if I just create the background div and don't apply any z-index to it, it ends up being on top of everything, and I cannot click on the box. If I set the z-index of the background div to be below the box, I can't seem to click on the background. What I want to do, it to be able to click both on the box, and the background.
var x = document.getElementById("bg");
x.addEventListener("click",reset,false);
function reset() {
alert("reset was clicked");
}
CLARIFICATION: box is on the same node level as the bg. it is not inside the bg div.
Take a look at this jQuery plugin - even if it doesn't solve your particular question the code could provide insight into your dilemma.
jQuery clickoutside
You must post your code so every one can help you. My test work correctly on Firefox and Chrome. If I'm guessing right, the background in your code isn't expanded. Try to remove html, body { width:100%; height:100%; } in my example to see the problem.
On IE browser, you need to use a transparent gif image as background of the background div, otherwise the background div may be unable to receive mouse click event.

Invisible elements don't receive mouse events

I'm writing a swatch picker in jquery for a site that allows you to specify a colour for a seat cover. The picker consists of a grid of thumbnail images, when the user mouses over each of these thumbnails, a bigger image is shown over the top.
Now the thing is, the client wants the images that are partially or totally obscured by the overlying bigger image to still respond to events.
My solution to this problem was to add a preview element for showing the bigger picture to the list with a z-index of 5. Then I'd clone the original set of elements in the swatch list and overlay them as invisible elements with a z-index of 10. The result is that the partially obscured elements appear to still respond to mouse events, though in actuality the underlying elements don't have events attached. The events are actually attached to invisible elements in front of the preview element (I hope that makes sense!).
My first attempt to achieve this effect was for the cloned elements to get a visibility: hidden CSS style, but these don't respond to mouse events. I tried using empty elements with background: transparent instead, and this seemed to work fine, but testing in IE9 revealed that these elements don't respond to mouse events either!
I can get it to work if I remove the background:transparent style from the overlay elements, bot of course now they obscure everything underneath.
It only seems to be IE9 that has this issue so far. IE8 appeared to trigger the events on transparent items fine. It also seems to work as intended in FireFox and Chrome.
The solution in the end was annoyingly simple. All that was needed was to give the invisible elements the following styling:
background-color: white;
opacity: 0;
filter: alpha(opacity=0); /* for old IE versions */
This leaves the elements invisible, but still responsive to mouse events.
I would use a double binding technique for this, where the mouseover is bound to the behind image, and the out is bound to the front image. that allows you to have the front image hidden until the behind image is hovered.
// use $.fn.each so that each thumb gets its own timer.
$(".thumb-behind").each(function(){
var timer;
$(this).hover(function(){
$(this).next().stop(true,true).fadeIn();
},function(){
timer = setTimeout(function(){
$(this).next().stop(true,true).fadeOut();
},10);
});
$(this).next().hover(function(){
clearTimeout(timer);
},function(){
$(this).stop(true,true).fadeOut();
});
});
just make sure you modify $(this).next() to select the larger thumbnail in relation to the current thumbnail.

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