Develop Reference

Adding touch swipe support in react

I've been struggling with adding support for touch devices. The app works really well on desktop devices. So you can hover over the td element, then once you click and drag the td, the selection functionality is triggered, if the word is found the resultWords var then set it as marked, otherwise set selection to false.
There's a codesandbox for it:
https://codesandbox.io/s/determined-turing-50zbpj?file=/src/index.js
I am trying to add the same functionality for the touch devices, so onTouchStart is supposed to add the first letter to array and once the swiping over td's is happening then keep adding the letters, word found -> set it as marked, otherwise -> set selection to false.
I have tried using onTouchStart combined with onTouchMove (all in the td element). onTouchStart seems to work fine, although onTouchMove always brings back the first letter where the gesture was first triggered.
Any suggestions how I could move on with this?

How to focus scrollable elements like mouse click without "tabindex" in Google Chrome

I'm creating an keyboard navigation extension which need to focus an scrollable element to scroll it for Google Chrome. Because this is just an extension, so I want not to edit existing DOMs like another similar question.
I want to focus an element like "mouse click to a scrollable element". Mouse click to an scrollable element, and then you can scroll the element by arrow keys. This has the following feature:
No focus visual effect
"tabindex hack" change the element like a focused textarea border.
No change document.activeElement
No change attributes
I read some similar OSS sources like vinium, but these are scrolling by javascript, or do nothing for scrollable elements. So I think there seems to be no way.

Focusing input with selected text causes scroll to top

I'm running into this problem on Chrome. When I use jQuery to focus on an HTML input with part of its text selected, my page jumps to the top instead of the element itself. I've created the following jsfiddle as an example:
http://jsfiddle.net/wzs821jg/3/
I've put margins above and below each input, enough to create a scrollbar. If your resolution is taller than mine (I'm on a laptop) and you have no scrollbar, just add more margin until you do.
Add enough text to the second input to cause it to scroll (overflow on the x). You can just add jibberish, such as "asdfkasdkjfhakjsdhfaksdjhfkajshdkfajshdkfajshdkfjah", which should work fine. Once you've gotten enough text, highlight a portion of it. Now there are two methods you can use to cause the page to scroll to top:
Click the button, which has a short jQuery listener that will focus on the second input.
Focus the first input and then press tab to focus the second input
On Chrome Version 41.0.2272.101 (64-bit) on OSX Yosemite, both of those actions should cause the window to jump to top instead of focusing on the second input. I've tried on Safari, and I can't recreate the issue. I've experienced different behaviors depending on where you select the text (outside, inside, or across the overflow) and the method used to focus. Play around with it a bit.
My question is: is this a problem with Chrome or am I doing something wrong?
Edit: I've filed a bug report with Chrome pointing to this question. Unless someone has an answer, I'm just going to assume it's simply a bug within the browser.

Limiting an editable div area by height, simulating onkeyup event in Javascript

I know there are many similar topics but none of them has the solution to my problem so please read my question carefully before sending similar topic links and marking as duplicate question.
I have a content editable DIV object, something similar to TextArea control. My goal is to cancel key press events if content starts scrolling and there must be no flickering.
When i use keyUp event, it's too late to cancel and there is also no methods available to cancel changes. What's done is done at this stage.
When i use keyDown or keyPress events, they are cancelable. But new changes are not yet applied. So, i know which character is pressed etc. but i still don't know how it's going to affect the scrolling size.
Plus, i allow style changes like making the text bold or changing the font size. Since there is;
document.execCommand("undo");
command, i'm able to test these changes and undo if scrolling starts. To test things, i use a cloned div with same content. It works fine. Changes are applied to cloned div (which is visible at the moment for debugging purposes but will be invisible if the method works) and if cloned div has an overflow, changes are canceled.
My problem is at doing the same thing for key presses. It's harder to simulate what happens to editable div content than using document.execCommand for other styling options. What i need is to get the innerHTML result at keyUp stage before keyUp occurs and event is still cancelable like keyDown or keyPress.
To simulate things, i tried getting cursor position and adding pressed characters manually using substring function but content isn't plain text and i had many problems with it. For instance when i press enter, an HTML block <div><br></div> is added for newline character which messed up cursor position. I tried many ways to handle things but it's very open to bugs. So, i decided not to follow this path.
In short my question is;
How can i possibly limit an editable div area by height, not allowing
to overflow or scroll without any flickering, just canceling key press
events? Do i have to simulate something like willKeyUp or is there any
other cross browser way?
Here is jsfiddle link for my sample which works for document.execCommand case (changing font size, weight etc.) but fails at typing letters;
http://jsfiddle.net/7zQD2/
Edit: To clarify my goal at jsfiddle example, after writing 5 lines of text, either when you press enter or type to end of the line, cursor should never reach to the sixth line. Key presses should be canceled and cursor should stay at fifth line with no content changes or flickers.

One solution is to use the cloning setup you already have, but to set the opacity of the first copy to 0 and position it on top of the clone with position: absolute in the css. The first copy won't be visible, but will catch a click directed towards the visible one underneath it. You can change your event to fire on keyup.
Since the transparent div still exists, and still has height, it can measure text height for you without being visible to the user. The visible text then updates to match what is learned with the transparent text, and never reaches the 6th line or flickers.
http://jsfiddle.net/7zQD2/2/

Html scroll: how to avoid it to "cut" my inner elements

this question is for an autocomplete drop down list I have to do that will fire while you're writing in an html textbox.
It basically consists of a div containing the suggestion elements, each of them being a div as well.
I got to the point where it's begining to work properly but now I added a vertical scroll to the containing div so you can limit the height of the drop down list, and I got the following behaviour:
If you use the scroll, it scrolls up or down in "pixels", so it cuts my elements making it all look anything but sleek.
I'd like to override the behaviour to go up and down one whole div element when you use the scroll. I don't even know how to google for this...
Anybody knows any useful resource about this or can give any tip as to where to start, if it's possible to override the scroll movement events or I should look into another direction?
Thanks a lot in advance
Note: I cannot use jquery autocomplete plugin.

You could implement your own scrollbar, using mouse events and updating positions manually.

Could you not tap into a 'scroll' event for that element (DOM 3 Events provides a scroll event for an element, not sure how supported it is), such that whenever the scroll position is changed, it calls a little routine of your own that adjusts the scroll position by rounding it to the nearest 'notch'?
Or, you could regularly poll for the scroll position and adjust it when it has moved. This scroll position seems fairly cross-browser.

First:
Using your own scroll bar, make a scroll event handler. Here you could use an animation by delta ( it is found in evt ) on which you can set the scrollTop of the element yourself by the offsetHeight of your top or bottom visible element. Also if the div height does cut off an element just make the previous or next element a bit "higher" aka set it's height to push the cut off element up or down.
Second:
You could "patch" the div so only a few elements would be visible. and while you scroll you hide the top one and display the bottom one in a animation, without using scrollTop or scrollHeight.
Watch out for scroll event in Firefox. It has another name, but you can test it like this:
eventName = eventName === 'mousewheel' ? ((/Firefox/i.test(navigator.userAgent)) ? "DOMMouseScroll" : eventName) : eventName;
Good Luck. If you need any help in about 2 days i will have it implemented, because i need one too.

This simply cannot be done, there is no solution, period. One must live with this limitation.
Why is there no solution?
Because even if you implement your own scroll bar, you would still have to rely on scroll events, and these can be neither canceled nor prevented from bubbling to the body element. Really, they can't, you can call preventDefault() and stopPropagation() on them till the cows come home and they still bubble. This is a deliberate decision on the part of the standardizing body and browser implementors.
If scroll events were cancellable, EхpеrtEхchangе could prevent you from scrolling to the bottom of the page to see the answer ;) (don't worry, I used some Cyrillic letters in "EхpеrtEхchangе" so they don't get an indexable mention).