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Tabs default action is not stopped event though i use e.preventDefault()

I am showing a text area in a modal when I pressed tab it moves to the next input I wrote code to stop this but I didn't work for me.(when I pressed tab the execution even not coming to the acceptTabsSpace function)
$(document).on("keyup", "#collection-text-input", acceptTabsSpace);
function acceptTabsSpace(e){
var keyCode = e.keyCode || e.which;
if (keyCode == 9) {
e.preventDefault();
return false;
}
}

Add the listener to trigger on keydown instead:
$(document).on("keydown", "#collection-text-input", acceptTabsSpace);
function acceptTabsSpace(e){
var keyCode = e.keyCode || e.which;
if (keyCode === 9) {
e.preventDefault();
return false;
}
}

Use keydown instead key up and for tabspaces press tab twice.
$(document).on("keydown", "#collection-text-input", acceptTabsSpace);
function acceptTabsSpace(e) {
var keyCode = e.keyCode || e.which;
if (e.keyCode === 9) {
e.preventDefault();
this.value = this.value.substring(0, this.selectionStart) + "\t" +
this.value.substring(this.selectionEnd);
this.selectionEnd = s + 1;
}
}

Is there a way in JavaScript to change Enter to Shift + Enter

This is what I tried and obviously failed:
ed.on('keyup', function(e){
console.log(e.keyCode)
if(e.keyCode == 13 && !e.shiftKey){
e.shiftKey = true;
e.keyCode = 13;
$(this).trigger(e);
}
else if (e.keyCode == 13 && e.shiftKey){
e.shiftKey = false;
e.keyCode = 13;
$(this).trigger(e);
}
});
Is there a way to do this cause based on what I seen I think I'm on the right track and most likely just not triggering it early or something similar.
Additionally, I tried using 'keypress' instead and had no luck with that.

document.onkeydown = function onkeydown(e) {
if (e.keyCode == 13 && e.shiftKey==false) {
e.preventDefault();
document.execCommand("insertLineBreak");
}
}

When enter is pressed without shift, trigger keydown with enter and shift!
$('input').on('keydown', function(event) {
if (event.keyCode == 13 && !event.shiftKey) {
$(this).trigger(jQuery.Event("keydown", {
keyCode: 13, // ENTER
shiftKey: true
}));
} else if (event.keyCode == 13 && event.shiftKey) {
console.log('shift + enter');
}
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input/>

Adding keypress Events that use an existing function

I have used a function which is activated on click events. I want to do the same using keypress events.
function addToText(target) {
var exp = target.target;
//alert(exp.value);
if (newExp) {
//clearText();
document.getElementById("expression").value = exp.value;
newExp=false;
}
else
document.getElementById("expression").value = document.getElementById("expression").value + exp.value;
}
This is the function used. How do I modify it to use for keypress events also. Currently, it does not work initially(for keypress events). But after clicking once, then any keypress returns the same number that was previously clicked.
Full code here:http://codepen.io/jpninanjohn/pen/JXVpYb?editors=1010

Here's is your final solution, I test if charcode is between 48 and 57, what it means, numbers between 0 and 9.
document.addEventListener('keypress', function(e){
if (e.which >= 48 && e.which <= 57)
document.getElementById("expression").value+= String.fromCharCode(e.which);
});

You can use this function-
window.onkeyup = function(e) {
var key = e.keyCode ? e.keyCode : e.which;
document.getElementById("expression").value += key-48; //for getting the number
alert(key);
if (key == 38) {
//whatever
}else if (key == 40) {
// whatever
}
}
source
And you need to add + to the =
document.getElementById("expression").value+=
instead of -
document.getElementById("expression").value=

You have to add a different function for keyPress event, because the keypress event get the value of pressed key differently, not target.target
function addToTextKeypress(event) {
var exp = String.fromCharCode(event.keyCode);
//alert(exp);
if (newExp) {
//clearText();
document.getElementById("expression").value = exp;
newExp=false;
}
else
document.getElementById("expression").value = document.getElementById("expression").value + exp;
}
Later you need to remove exp.value since it has the direct value

How to limit Tab listener to callback only if the textbox has change

I'm trying to implement a Tab key listener for a textbox.
$('#mytextbox').live('keydown', function (e) {
if (e.keyCode == 9 || e.which == 9) {
// TO DO SOMETHING
}
});
However, for some reason I need to limit the tab listener's callback to invoke only when the textbox has changed. Is there anyway to do this?

You might be able to check the value of the input field to make sure it's different from it's original value?
E.g.
$('#mytextbox').live('keydown', function (e) {
if ((e.keyCode == 9 || e.which == 9) && ($('#TextBox').val() != 'Starting Value')) {
// TO DO SOMETHING
}
});

You can do it just like:
var data = "";
$('#mytextbox').live('keydown', function (e){
if(e.which == 9 || e.keyCode == 9){
if($(this).val() != data){
alert('changed!');
data = $(this).val();
}
}
});
http://jsfiddle.net/DDCZS/1/

Or without storing / knowing value of that textbox:
var changed = false;
$('#mytextbox').on('keydown', function (e) {
if (e.which == 9 && changed) {
e.preventDefault();
// TO DO SOMETHING
alert("works");
changed = false;
} else {
changed = true;
}
});
http://jsfiddle.net/9a37b/

Disable backspace and delete key with javascript in IE

Anyone know how can I disable backspace and delete key with Javascript in IE? This is my code below, but seems it's not work for IE but fine for Mozilla.
onkeydown="return isNumberKey(event,this)"
function isNumberKey(evt, obj)
{
var charCode = (evt.which) ? evt.which : evt.keyCode
if (charCode == 8 || charCode == 46) return false;
return true;
}

This event handler works in all the major browsers.
function onkeyup(e) {
var code;
if (!e) var e = window.event; // some browsers don't pass e, so get it from the window
if (e.keyCode) code = e.keyCode; // some browsers use e.keyCode
else if (e.which) code = e.which; // others use e.which
if (code == 8 || code == 46)
return false;
}
You can attach the event to this function like:
<input onkeyup="return onkeyup()" />

update based on #JoeCoders comment and the 'outdatedness' of my answer, I revised it.
document.querySelector([text input element]).onkeydown = checkKey;
function checkKey(e) {
e = e || event;
return !([8, 46].indexOf(e.which || e.keyCode || e.charCode) > -1);
}
See also this jsFiddle

This code cancels backspace action.
window.onkeydown = function (event) {
if (event.which == 8) {
event.preventDefault(); // turn off browser transition to the previous page
// put here code you need
};
};

$(document).keydown(function(e) {
if (e.keyCode === 8) {
var element = e.target.nodeName.toLowerCase();
if ((element != 'input' && element != 'textarea') || $(e.target).attr("readonly")) {
return false;
}
}
});