Develop Reference

Disable Chrome's scroll preserving feature

I have a page containing a list of items:
Load more button should load some more items via ajax and append it to the items container preserving current scroll position. So after I click it the feed I expect it to look like this (green items are new):
But in fact Chrome 56 executes some computations to make the page stay in the same state, and what I see looks like this:
Is there any way to prevent this smart scrolling position setting in Chrome?
Update: I can reproduce the behavior only if parent container ('body' in my case) has 'display: flex' property (I use it to achieve 'sticky footer' feature).

I solved a similar problem by adding overflow-anchor: none; to the scroll container.
https://wicg.github.io/ScrollAnchoring/

Today it seems that this property was excluded? When adding 'overflow-anchor: none;' as style on a div element I get the message: Validation (CSS 3.0): "overflow-anchor" is not a known css property name.

This is simple. Before performing your AJAX call, save the scroll position of the page to a variable, then, after the call, scroll to the position indicated by that variable. Here is what you should write before your AJAX call:
var scrollpos = window.scrollY;
and here is the code after your AJAX call
window.scrollTo(0,scrollpos)
Hope this works

Why chrome makes calculations to preserve the scroll position? Usually the page will only be longer, so the scroll position stay fixed anyway.
I assume you remove the button, so the position cannot be kept, while content was not reloaded. You should reserve the button space in the dom and remove the reserved space when inserting the reloaded items.

Adding an absolute positioned element causes line break

So I have a "cursor" object created like so:
var cursor=document.createElement('span');
cursor.id="currentCursor";
cursor.innerHTML="|";
cursor.style.fontWeight="bold";
cursor.style.position = 'absolute';
cursor.style.marginLeft="-1px";
Then I add it to the page where someone clicks with this:
var selection = window.getSelection();
var currentRange = selection.getRangeAt(0);
currentRange.insertNode(cursor);
The problem I'm running into is in certain places (mainly end of lines) if the cursor object is added it creates a line break before the object. Using insertNode to move it to another area removes the line break. Also if I set the display to "none", wait for a few seconds and then set it back to "inline" the line break is removed.
This seems like maybe a browser bug in adding absolute elements, but I was wondering if someone had a workaround. I've tried setting the width to 0px but it has no effect.
Update
So if I change the cursor to
cursor.style.position = 'static';
It doesn't have random line breaks. However this causes space to be created around the element. Any way to not allow elements to create space around them?
Update 2
Added a fiddle to show the problem:
http://jsfiddle.net/Mctittles/pSg2D/1/
Original code is a bit large but I slimmed it down to highlight this problem.
If you click at the end of the smiley face and then type it causes line 33 to trigger creating a new text node. After typing a couple letters you'll see the cursor object is forced to the next line. Clicking somewhere else to move it makes the lines merge again.
If you un-comment lines 38 and 40 you'll see what I was talking about with making it initially display:none and changing it later. This time it doesn't cause a line break.
I took out some cross-browser code for fiddler, so this might only work in Chrome

However [position:static] causes space to be created around the element.
No, it doesn’t cause it – there is no actual space created “around it”, it’s just the display width of a character plus spacing in the used font, and that gives the span element itself a width that is more than the | character itself. But when you position the element absolutely, you don’t notice that, because it is taken out of the flow, so it doesn’t push the following characters to the right.
My workaround proposal: Don’t put | into the span as innerHTML, but leave it empty – and then implement the line by giving the element a border-left:1px solid. Remove position:absolute, so that it defaults to static.
Then you might probably not like the height your cursor is getting with that – but that can be fixed as well, by setting display to inline-block, and giving it a height as well.
Here, see how you like ’dem apples: http://jsfiddle.net/pSg2D/9/

You should use CSS instead. Using z-index and maybe even float would (atleast should) fix this.
Edit: Always make sure no other styles make it break line!

How to have transparent fonts except for the 'text-caret' in a textarea?

I have a simple textarea and I need to make transparent letters while allowing the text-caret to be visible. When I apply the following rules then I get invisible caret:
textarea {
background: transparent;
opacity: 0;
}
When I type invisible text, I need to see the text-caret move.
EDIT: I need to make editor to edit td cell in table. When I click on a cell I show a textarea and start typing. On a each character letter, I insert a context in a cell. After that, I hide a textarea.

This jsFiddle DEMO uses an online tutorial method that has been slightly modified to create a non-native browser text-caret along with transparent text.
Also, this jsFiddle New Method I created handles that goal differently but isn't IE8 friendly.
Status Update: I've improved the above jsFiddle DEMO with this newer version titled:
jsFiddle New Method that's Newer!!
The above jsFiddle version now allows the inside of the text-area to be clicked and the caret will respect that clicked location. This extra functionality was made possible by a great question and answer here.

Time to throw my $0.02 in.
This is an answer to the question, as I understood it, that works, it's quick and dirty, so feel free to make suggestions. This code is untested, but I did create a working fiddle here: http://jsfiddle.net/66RXc/
<html>
<head>
<title>Testing</title>
<script type="text/javascript">
<!--
function call(val) {
document.getElementById('result').value += val.charAt(val.length - 1);
document.getElementById('result').value =
document.getElementById('result').value.substr(0, val.length);
document.getElementById('test').value =
document.getElementById('test').value.replace(/[^\^]/g, ' ');
}​
-->
</script>
</head>
<body>
<textarea name="textarea" cols="20" rows="5" id="test"
onKeyUp="call(this.value);"></textarea>
<textarea style="display:block" cols="20" rows="5" id="result" disabled>
</textarea>​
</body>
</html>
The way I approached it was every time a character is typed in textarea "test", copy it over to a hidden text box, and replace all the characters in "test" except ^ with spaces. The characters are hidden, and the carat is still there. The full text is still in the other box. You could use display:hidden instead of display:block to hide it.
This isn't exactly the best implementation in the world, just something I did quickly. You have to type kind of slow (~15-20 WPM) for it to work.

Here is a CSS3 solution for making the text, itself, transparent:
Set the color attribute to be color: rgba(0,0,0,0); for the text
The only problem is that the caret goes invisible to. I did a quick search and found out that the caret and its styling are completely at the disposal of the browser. As such, the only option that I can think of for you is to use Javascript to add a simulated caret to the end of what you are typing.
I have an idea of how to do this, but it's messy and I wouldn't exactly call it ideal - I am, however, going to write it in case it helps further someone else's idea:
add a hidden label to the page
make sure it's hidden and not display: none; (so that it has actual width)
set white-space: nowrap; to keep it all on one line)
make sure the text is styled exactly the same as the text in the textarea
add the element <span id="caret">|</span> right before the textarea (I will refer to this as the caret for the rest of the spec)
set its position to position: relative;
increase its z-index to make it overlay
shift it right in order to set it on top of where the ACTUAL caret's initial position would be
make a function to check take in the value of the textarea and check the width of the textarea against the position of the caret (lookup selectionStart if you don't know how to do this)
the problem here is that characters are not always the same length, nor are they always the same length as their counterparts in other fonts
to solve this, as text is entered into the textarea you should have it imitated in the hidden label you created in step 1
imitate only the text from the start of the textarea to the caret's current position
wrap each character (including spaces) in their own span
next you will have to call a function to compare the width of the label with the width of the textarea
if the label is less wide than the textarea, get the width of the last span in the hidden label and shift the caret to the right by that width, then move on to step 4
as this is function will be run as text is entered it will happen one character at a time
be careful here that the caret doesn't go outside the textarea when it's in its last and near last positions
if the label is wider than the textarea:
add the widths of the characters (spans) in the label one at a time until you reach the width of the textarea
shift the position of the caret down by the height of the font and back to the horizontal starting position (as the caret's position is relative, just change its left position back to (0 + offsetToACTUALCaretPosition)
use a flag (e.g. class="break") to mark the last span (character) in the previous row
call the width comparison function again
make sure that you include a condition to check for the flags that you added at the end of each "row" (if any)
if you haven't already, apply any desired CSS styles to the caret span and change the color of the textarea's text to be color: rgba(0,0,0,0);
Caveats:
this will have a lot of overhead for the tiny job it does
you will have to adjust this method to account for padding
you will have to adjust this method to add support for deleting characters and moving the carets to an earlier position (to the left)
if you leave the textarea scrollable, you will have to add support for that (also for similar settings, like static heights causing text to scroll or move off screen/out of the textarea's visible area)
As I said before, I know that this solution is very rough, but it may help someone come up with a better one.
Good luck!

Based on your edit, if you need to just hide a textarea why don't you use jQuery $('#your_id').hide();

different caret position on firefox and IE

To recreate the problem, please visit http://jsfiddle.net/BsJ6V/ and type any character right after the opening body tag (for example, <body>h if you type the h character).
An alert box will display the caret position. When you run it in Firefox the caret position is 56, when you run it in IE it is 60. Could you please what the matter is?
EDIT::
UPDATED LINK.

The difference is because IE counts each line break within a textarea as two characters (CRLF, or \r\n) while Firefox counts it as a single LF (\n) character.
Your function won't get the right caret position in IE if there are leading line breaks. To see this, place the caret at the start of the textarea in your first jsFiddle example and press return a few time and trying typing in one of the empty lines. To fix this, you can use a function I've posted before on Stack Overflow or if you prefer a jQuery plug-in, I've created one for dealing with textarea selections: http://code.google.com/p/rangyinputs/
UPDATE
Note that jQuery's val() method normalizes this difference in line breaks between browsers (unhelpfully, in my view, since the value that gets sent to the server isn't normalized) so that line breaks are always \n. Both my plug-in and your function return a caret position relative to the textarea's raw value property, not jQuery's normalized value, so if you are manipulating the value using the caret position, you need to use $textarea[0].value instead of $textarea.val().
You can see this difference here: http://jsfiddle.net/MyR7J/2/

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