DOM not visually updating with iOS scroll? - javascript

This is an odd one.
Let's say I have some text in a container with -webkit-overflow-scrolling:touch applied to it, and a span element with a background color within the content but outside of the viewport.
If you then press a button to remove the span element and replace the contents with the text inside, and then scroll the container so that the span element that was once there is in the viewport, the background color is retained. The span element itself is gone, but the DOM is not visually updated.
jsFiddle (view it on iOS) - http://jsfiddle.net/charlescarver/rdZq4/4/
Now, there are two solutions that I have found that I do not like, but update the container visually:
Remove the -webkit-overflow-scrolling:touch
Add the following code to change an aspect of the CSS, then back:
This method uses .scroll():
$(".text").scroll(function () {
$(".text").css("color", "blue");
setTimeout(function () {
$(".text").css("color", "#000");
}, 1)
});
Problem with this, the residual background color is there until the scrolling stops, which still leaves the artifact.

Related

jQuery cycle photos in div background

I've accomplish successfully when the mouse overs a div to cycle and change the background-image and stop the other divs from cycle.
What happens is that, this div have a title which appears when the mouse is hovering the div, and if I grab the cursor and put it over the title and then move the cursor again to the other div title, the cycle continues in both divs, and I would like not to.
I'm clearing the interval cycle this way: clearInterval(theInterval);
But, somehow, when the title is being hovered it doesn't stop the others cycle.
The problem can be seen in JSFiddle.
Simulate the problem:
Put your cursor over the title
Move your cursor quickly to the other div title
You'll see that both divs continue the cycle independently (and I want only one to cycle)
Simulate how it works:
Put your cursor over the div (without being in the title)
Move your cursor to the other div
You'll see that only one div cycles
I believe it's a problem with the nature of the mouseover event, and the divs being in such close proximity. Try using the hover event instead. See this fiddle
In essence:
$('.collection-photo').hover(function(){
// mouse over stuff here
}, function() {
// mouse out stuff here
});

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.

Apply gradient over page without hindering user interaction [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.

Scrolling textarea to specific area with javascript

I have a textarea with a scrollbar. I need to change the position of your cursor in the textarea with javascript AND scroll the textarea so your cursor is visible. I am using elem.selectionStart and elem.selectionEnd to move your cursor, but when I move it to a point that is not visible, the textarea does not scroll so the cursor is visible.
More details (probably TL;DR)
I am creating a slideshow editor and have a preview of the complete slideshow next to an editor (textarea with scrollbar) for the content. As you move your cursor through the textarea, the slideshow changes slides so you are always viewing the slide that you are editing. I need to get it so changing the slide (using buttons) moves your cursor so you can see the code that generated that slide.
// slideBoundries has numbers which are the indexes where the slides begin/end
// eg: [0, 81, 140, 250] for slideshow with 3 slides
if (doc.editor.selectionEnd > slideBoundries[curSlide] &&
doc.editor.selectionEnd < slideBoundries[curSlide + 1]) {
return;
}
doc.editor.selectionStart = slideBoundries[curSlide];
doc.editor.selectionEnd = slideBoundries[curSlide];
I could just count the number of newlines in the file so I know how far to scroll down, but there are many lines that are long and take up multiple lines. I am using a monospaced font so counting the number of newlines and lines that take up multiple lines, but I would like an easier way. Is there a function I could call to mimic what happens when the user moves their cursor as the textarea always scrolls to that point when the user clicks...
EDIT:
Due to popular demand, here is a fiddle: http://jsfiddle.net/tShQ2/
The method I'm going to use to fix this issue is create a phantom textarea that has same width, but autosizes to height. It has to be visible or else it won't work, so make it abs position and move it off screen. Then put the text before the desired cursor position in it. Then scroll the real textarea to the height of the phantom textarea.
Your solution is a good one, but let me suggest a couple of things to make it easier.
Use a phantom div, rather than a textarea, since a div will autosize automatically. Just make sure to match the styles.
To hide your phantom div use:
visibility: hidden;
position: absolute;
This has the same effect as display: none, while allowing the div to have a height.
One more thing. For IE, you can create a range from the selection and scroll to it explicitly:
document.selection.createRange().scrollIntoView();

How do I stop a textarea from scrolling to the top whenever I change its value

I'm making something where a textarea gets more and more text appended. In firefox, the textarea scroll back up to the top each time.
I currently have something like textarea.scrollTop=1000000; to scroll it back down each time it changes, but it still goes up to the top for a very short time.
Is there any way to stop it doing so?
I ran into this problem, too. It happens in IE and Firefox but not Opera and Chrome.
I thought of hiding the momentary jumps to the top by "double-buffering" changes to the textarea:
Create two textareas with the exact same properties and dimensions. Only one of these is visible; the other one is hidden.
Append text to the hidden textarea: set [the value of the hidden textarea] to [the value of the visible textarea] + [text to append]. (The textarea will automatically scroll to the top, but this textarea is hidden!)
Scroll the hidden textarea to the bottom: set scrollTop to a high integer value like (-1 >>> 1).
Swap the hidden textarea with the visible one. Now the new text is shown, sans jumping to top!
You can swap the hidden/visible textareas by using one of two methods:
Use absolute positioning to place the textareas on top of each other in conjunction with toggling their visible property.
Swap the actual DOM elements. I'm not sure if this will introduce a new type of "flicker." You may have to create a div to contain the visible textarea so the layout of the page doesn't keep changing...
i thing that is problem of adding the content via the script, paste your code which append text to your textarea

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