Develop Reference

Delete characters from my last focused text field when div in pressed

I have a div (button) that when is pressed it deletes the characters of an specific text field. Now I am trying to change the code in a way that delete the characters of the last focused text field.
This is the code that only delete the characters of one text field:
$(".delete").on("mousedown",function(evt) {
var nameInput = document.querySelector("#name")
var cursorPosition = nameInput.selectionStart;
$("#firstName").val(
function(index, value){
return value.substr(0,cursorPosition - 1) + value.substr(cursorPosition);
});
nameInput.selectionStart = cursorPosition - 1;
nameInput.selectionEnd = cursorPosition - 1;
return false;
});
And this is what I haver for now:
$(".delete").on("mousedown",function(evt) {
var lastFocused;
$(".item").focusout( function(e) {
lastFocused = e.target;
});
var cursorPosition = lastFocused.selectionStart;
lastFocused.val(
function(index, value){
return value.substr(0,cursorPosition - 1) + value.substr(cursorPosition);
});
lastFocused.selectionStart = cursorPosition - 1;
lastFocused.selectionEnd = cursorPosition - 1;
return false;
});
The HTML:
<div class="delete key-btn">
<input id="firstName" name="firstName" type="text" class="item" required/>
<input id="firstName" name="firstName" type="text" class="item" required/>
In console, I'm getting the error: "Cannot read property 'selectionStart' of undefined". Can someone please tell me how to achive this? Thanks

This works:
// 1. this has to be declared globally
var lastFocused;
// 2. you need to set the event handler for the 'item' elements outside of the delete handler
// I'd also suggest using the 'focus' event here instead of 'focusout'
$(".item").focus(function(e) {
lastFocused = e.target;
});
$(".delete").on("mousedown", function(evt) {
// 3. need the null check if none of the inputs have been focused yet
if (!lastFocused) {
return;
}
var cursorPosition = lastFocused.selectionStart;
// 4. need to wrap this in the jQuery function to use val()
$(lastFocused).val(
function(index, value){
return value.substr(0,cursorPosition - 1) + value.substr(cursorPosition);
});
lastFocused.selectionStart = cursorPosition - 1;
lastFocused.selectionEnd = cursorPosition - 1;
return false;
});

You can return the target to the variable of lastFocused and your delete function should work.
I'm not sure what the rest of your code looks like, but this is my best guess as to what you're looking for. This will get rid of the error and you can log lastFocused.
lastFocused = $(".item").focusout( function(e) {
return e.target;
});

I explain better with code.
var focusedItems = [];
$('.item').on('focusin', function() { focusedItems.push( $(this) ); }
$('.item').on('focusin', function() { focusedItems.splice( $(this), 1 ); }
$('.delete').on('mousedown', function(evt) {
var lastFocused = focusedItems[ focusedItems.length - 1 ];
// do whatever you want
}
As you focus on a item you push in the array as a jquery reference, as you focusout you remove it. The last element is the last focused.

Trying to invoke onchange method set by jQuery

In my code, I am setting a change listener on my checkboxes here
$(".section").change(function() {
if($(this).is(":checked")) {
$("." + this.id).show();
...
Now I am trying to do a "code-driven" click on the checkbox, and I have
$(".secTitle").click(function(e) {
var elem = this;
while(elem) {
if (elem.className && elem.className.indexOf ('DOC_SECTION') != -1) {
var clzes = elem.className.split(" ");
var clzIdx = 1;
if (elem.getAttribute('closeSecClassIdx')) {
clzIdx = parseInt(elem.getAttribute('closeSecClassIdx'));
}
var chk = document.getElementById(clzes[clzIdx]);
chk.checked = false;
alert(chk.onchange);
//chk.changed();
break;
}
else {
elem = elem.parentNode;
}
}
});
I know that I have the right element, as chk.checked = false; is working correctly. After that I'm trying to invoke the change method set earlier but my alert is showing 'undefined'.

You can trigger the change event by calling $(chk).change(). Below I've created a little prototype that shows binding to the change event and invoking it.
jQuery(function($) {
// bind to the change event
$("input").change(function() {
console.log('change triggered!');
});
// now trigger it
$("input").change();
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="checkbox" />

How do I make "Enter" keypress in an <input> Element shift focus to the next <input> element on the page. (JavaScript)

How do I make make an Enter keypress in an <input> element shift focus to the next <input> element on the page?
I have a for loop that creates <li> elements with <input> elements inside. I need to make so that when the user hits enter on their keyboard, the website will focus on the next input field so that the user can enter the next player name without having to toggle between using their mouse and their keyboard.
I thought using the nextSibling property was the solution but it wont work because the <input> elements technically dont have any siblings because each of them is inside/are children of diferent <li> elements.
Here is my JavaScript:
for ( var i = 1 ; i <= numberOfPlayers ; i++ ){
var inputElement = document.createElement('input');
var liElement = document.createElement('li');
inputElement.setAttribute( 'type' , 'text' );
inputElement.setAttribute ( 'id' , 'name-input-' + i );
inputElement.setAttribute ( 'class' , 'name-input');
inputElement.setAttribute ( 'placeholder' , 'Enter a name for player ' + i );
liElement.appendChild(inputElement);
nameInputArray[i] = inputElement;
document.getElementById('name-list').appendChild(liElement);
inputElement.addEventListener( 'keypress' , function(event){
if ( event.which === 13 ) {
alert(this);
document.getElementById( 'name-input-' + (i+1)).focus();
}
} );
}
I tried using the "i" in the for loop and string concatenation to select the ID of the next element but the "i" variable isn't working either because by the time that code runs that "i" is equal to the highest number that it can be after the whole for loop has ran.

Problem:
The problem with your actual code is that i is always equal to numberOfPlayers+1 in the event handler callback function, so you were trying to focus on a null element, you can read more about JavaScript closures to see why i was always equal to numberOfPlayers+1.
Solution:
First you need to use the onkeypress event on your input, then test if the pressed key is the Enter, if it's pressed get the id of the current input, extract i value from it and focus on the next input element using the next id.
This is how should be your code:
inputElement.addEventListener('keypress', function(event) {
if (event.which === 13) {
var i = parseInt(this.id.charAt(this.id.length-1));
console.log(i);
if(i<=numberOfPlayers){
document.getElementById('name-input-' + (i + 1)).focus();
}
}
});
This is a working snippet:
var numberOfPlayers = 5;
var nameInputArray = [];
for (var i = 1; i <= numberOfPlayers; i++) {
var inputElement = document.createElement('input');
var liElement = document.createElement('li');
inputElement.setAttribute('type', 'text');
inputElement.setAttribute('id', 'name-input-' + i);
inputElement.setAttribute('class', 'name-input');
inputElement.setAttribute('placeholder', 'Enter a name for player ' + i);
liElement.appendChild(inputElement);
nameInputArray[i] = inputElement;
document.getElementById('name-list').appendChild(liElement);
inputElement.addEventListener('keypress', function(event) {
if (event.which === 13) {
var i = parseInt(this.id.charAt(this.id.length - 1));
console.log(i);
if(i<numberOfPlayers){
document.getElementById('name-input-' + (i + 1)).focus();
}
}
});
}
<ul id="name-list"></ul>

If you want to stick with vanilla JS, use this:
for (var i = 1; i <= numberOfPlayers; i++) {
var inputElement = document.createElement("input");
var liElement = document.createElement("li");
inputElement.type = "text";
inputElement.id = "name-input-" + i;
inputElement.className = "name-input";
inputElement.placeholder = "Enter a name for player " + i;
liElement.appendChild(inputElement);
nameInputArray[i] = inputElement;
document.getElementById("name-list").appendChild(liElement);
(function(i) {
inputElement.addEventListener("keypress", function(event) {
if (event.which === 13) {
alert(this);
document.getElementById("name-input-" + (i + 1)).focus();
}
});
})(i);
}

This is my solution.
Do not forget that the created <li> element needs to be appended to something like <body>. I have actually added a <ul> element and appended it to the <body> and then appended the <li> elements to the <ul> element.
If you use nextSibling, you do not need to keep elements in nameInputArray. I have not removed it to show how it should be initialized before you can use it in your loop. Also, nextSibling works in my solution since I have put all the <li>s under one <ul> which I think is the correct thing to do anyway.
Other than that, I just corrected a few things here and there. Let me know if you have more questions about this code.
function eventFunc(event) {
if (event.which === 13) {
var nextInput = event.target.parentElement.nextSibling.childNodes[0];
if (nextInput !== null)
nextInput.focus();
}
}
var numberOfPlayers = 4;
var nameInputArray = [];
var ulElement = document.createElement('ul');
document.body.append(ulElement);
for (var i = 0; i < numberOfPlayers; i++) {
var liElement = document.createElement('li');
ulElement.append(liElement);
var inputElement = document.createElement('input');
inputElement.setAttribute('type', 'text');
inputElement.setAttribute('id', 'name-input-' + i);
inputElement.setAttribute('class', 'name-input');
inputElement.setAttribute('placeholder', 'Enter a name for player ' + i);
inputElement.setAttribute('onkeypress', "eventFunc(event)");
liElement.appendChild(inputElement);
nameInputArray[i] = inputElement;
}
UPDATE: Getting each input box from parent <li> elements:
After comment from the OP, I see that they want a structure like this:
<ul>
<li>input box1</li>
<li>input box2</li>
<li>input box3</li>
</ul>
In this structure, each input box is the first child node of its parent <li> element. Therefore, we can still use nextSibling (as the OP intended to use) in this way:
nextInput = event.target.parentElement.nextSibling.childNodes[0];
This line first finds the parent <li> element, applies nextSibling to get the next li element and then gets the input box inside that element.

$('input').on('keyup', function(event){
if(event.keyCode == 13){ // 13 is the keycode for enter button
$(this).next('input').focus();
}
});
https://jsfiddle.net/jat1merL/
are you looking for this?
by the way, use keyup instead of keypress. if a key is hold it fires mass of keypress events in a speed you can't handle ;)

Cycle Focus to First Form Element from Last Element & Vice Versa

I have created a form with malsup's Form Plugin wherein it submits on change of the inputs. I have set up my jQuery script to index drop down menus and visible inputs, and uses that index to determine whether keydown of tab should move focus to the next element or the first element, and likewise with shift+tab keydown. However, instead of moving focus to the first element from the last element on tab keydown like I would like it to, it moves focus to the second element. How can I change it to cycle focus to the actual first and last elements? Here is a live link to my form: http://www.presspound.org/calculator/ajax/sample.php. Thanks to anyone that tries to help. Here is my script:
$(document).ready(function() {
var options = {
target: '#c_main',
success: setFocus
};
$('#calculator').live('submit', function() {
$(this).ajaxSubmit(options);
return false;
});
$(this).focusin(function(event) {
var shiftDown = false;
$('input, select').each(function (i) {
$(this).data('initial', $(this).val());
});
$('input, select').keyup(function(event) {
if (event.keyCode==16) {
shiftDown = false;
$('#shiftCatch').val(shiftDown);
}
});
$('input, select').keydown(function(event) {
if (event.keyCode==16) {
shiftDown = true;
$('#shiftCatch').val(shiftDown);
}
if (event.keyCode==13) {
$('#captured').val(event.target.id);
} else if (event.keyCode==9 && shiftDown==false) {
return $(event.target).each(function() {
var fields = $(this).parents('form:eq(0),calculator').find('select, input:visible');
var index = fields.index(this);
var nextEl = fields.eq(index+1).attr('id');
var firstEl = fields.eq(0).attr('id');
var focusEl = '#'+firstEl;
if (index>-1 && (index+1)<fields.length) {
$('#captured').val(nextEl);
} else if(index+1>=fields.length) {
if ($(this).val() != $(this).data('initial')) {
$('#captured').val(firstEl);
} else {
event.preventDefault();
$(focusEl).focus();
}
}
return false;
});
} else if (event.keyCode==9 && shiftDown==true) {
return $(event.target).each(function() {
var fields = $(this).parents('form:eq(0),calculator').find('select, input:visible');
var index = fields.index(this);
var prevEl = fields.eq(index-1).attr('id');
var lastEl = fields.eq(fields.length-1).attr('id');
var focusEl = '#'+lastEl;
if (index<fields.length && (index-1)>-1) {
$('#captured').val(prevEl);
} else if (index==0) {
if ($(this).val() != $(this).data('initial')) {
$('#captured').val(lastEl);
} else {
event.preventDefault();
$(focusEl).select();
}
}
return false;
});
}
});
});
});
function setFocus() {
with (document.calculator)
var recap = document.getElementById(recaptured.value);
if (recap!=null) {
setTimeout(function() {
if (recap.getAttribute('type')=='text') {
recap.select();
} else {
recap.focus();
}
}, 100 );
}
}
Edit #1: I made a few minor changes to the code, which has brought me a little closer to my intended functionality of the script. However, I only made one change to the code pertaining to the focus: I tried to to disable the tab keydown when pressed on the last element (and also the shift+tab keydown on the first element) in an attempt to force the focus on the element I want without skipping over it like it has been doing. This is the code I added:
$(this).one('keydown', function (event) {
return !(event.keyCode==9 && shiftDown==true);
});
This kind of works. After the page loads, If the user presses tab on the last element without making a change to its value, the focus will be set to the second element. However, the second time the user presses tab on the last element without making a change to its value, and every subsequent time thereafter, the focus will be set to the first element, just as I would like it to.
Edit #2: I replaced the code in Edit #1, with code utilizing event.preventDefault(), which works better. While if a user does a shift+tab keydown when in the first element, the focus moves to the last element as it should. However, if the user continues to hold down the shift key and presses tab again, focus will be set back to the first element. And if the user continues to hold the shift key down still yet and hits tab, the focus will move back to the last element. The focus will shift back and forth between the first and last element until the user lifts the shift key. This problem does not occur when only pressing tab. Here is the new code snippet:
event.preventDefault();
$(focusEl).focus();

You have a lot of code I didn't get full overview over, so I don't know if I missed some functionality you wanted integrated, but for the tabbing/shift-tabbing through form elements, this should do the work:
var elements = $("#container :input:visible");
var n = elements.length;
elements
.keydown(function(event){
if (event.keyCode == 9) { //if tab
var currentIndex = elements.index(this);
var newIndex = event.shiftKey ? (currentIndex - 1) % n : (currentIndex + 1) % n;
var el = elements.eq(newIndex);
if (el.attr("type") == "text")
elements.eq(newIndex).select();
else
elements.eq(newIndex).focus();
event.preventDefault();
}
});
elements will be the jQuery object containing all the input fields, in my example it's all the input fields inside the div #container
Here's a demo: http://jsfiddle.net/rA3L9/

Here is the solution, which I couldn't have reached it without Simen's help. Thanks again, Simen.
$(document).ready(function() {
var options = {
target: '#c_main',
success: setFocus
};
$('#calculator').live('submit', function() {
$(this).ajaxSubmit(options);
return false;
});
$(this).focusin(function(event) {
$('#calculator :input:visible').each(function (i) {
$(this).data('initial', $(this).val());
});
return $(event.target).each(function() {
$('#c_main :input:visible').live(($.browser.opera ? 'keypress' : 'keydown'), function(event){
var elements = $("#calculator :input:visible");
var n = elements.length;
var currentIndex = elements.index(this);
if (event.keyCode == 13) { //if enter
var focusElement = elements.eq(currentIndex).attr('id');
$('#captured').val(focusElement);
} else if (event.keyCode == 9) { //if tab
var newIndex = event.shiftKey ? (currentIndex - 1) % n : (currentIndex + 1) % n;
var el = elements.eq(newIndex);
var focusElement = el.attr('id');
if ($(this).val() != $(this).data('initial')) {
$('#captured').val(focusElement);
} else if ((currentIndex==0 && event.shiftKey) || (currentIndex==n-1 && !event.shiftKey)) {
event.preventDefault();
if (el.attr('type')=='text') {
$.browser.msie ? "" : $(window).scrollTop(5000);
el.select().delay(800);
} else {
$.browser.msie ? "" : $(window).scrollTop(-5000);
el.focus().delay(800);
}
} else if (el.is('select')) {
event.preventDefault();
if (el.attr('type')=='text') {
el.select();
} else {
el.focus();
}
}
}
});
});
});
});
function setFocus() {
with (document.calculator)
var recap = document.getElementById(recaptured.value);
if (recap!=null) {
setTimeout(function() {
if (recap.getAttribute('type')=='text') {
recap.select();
} else {
recap.focus();
}
}, 1 );
}
}
I put my files available to download in my live link: http://www.presspound.org/calculator/ajax/sample.php

How can I check if a value is changed on blur event?

Basically I need to check if the value is changed in a textbox on the 'blur' event so that if the value is not changed, I want to cancel the blur event.
If it possible to check it the value is changed by user on the blur event of an input HTML element?

I don't think there is a native way to do this. What I would do is, add a function to the focus event that saves the current value into a variable attached to the element (element.oldValue = element.value). You could check against that value onBLur.

Within the onblur event, you can compare the value against the defaultValue to determine whether a change happened:
<input onblur="if(this.value!=this.defaultValue){alert('changed');}">
The defaultValue will contain the initial value of the object, whereas the value will contain the current value of the object after a change has been made.
References:
value vs defaultValue

You can't cancel the blur event, you need to refocus in a timer. You could either set up a variable onfocus or set a hasChanged variable on the change event. The blur event fires after the change event (unfortunately, for this situation) otherwise you could have just reset the timer in the onchange event.
I'd take an approach similar to this:
(function () {
var hasChanged;
var element = document.getElementById("myInputElement");
element.onchange = function () { hasChanged = true; }
element.onblur = function () {
if (hasChanged) {
alert("You need to change the value");
// blur event can't actually be cancelled so refocus using a timer
window.setTimeout(function () { element.focus(); }, 0);
}
hasChanged = false;
}
})();

Why not just maintaining a custom flag on the input element?
input.addEventListener('change', () => input.hasChanged = true);
input.addEventListener('blur', () => 
{
if (!input.hasChanged) { return; }
input.hasChanged = false;
// Do your stuff
});
https://jsfiddle.net/d7yx63aj

Using Jquery events we can do this logic
Step1 : Declare a variable to compare the value
var lastVal ="";
Step 2: On focus get the last value from form input
$("#validation-form :input").focus(function () {
lastVal = $(this).val();
});
Step3:On blur compare it
$("#validation-form :input").blur(function () {
if (lastVal != $(this).val())
alert("changed");
});

You can use this code:
var Old_Val;
var Input_Field = $('#input');
Input_Field.focus(function(){
Old_Val = Input_Field.val();
});
Input_Field.blur(function(){
var new_input_val = Input_Field.val();
if (new_input_val != Old_Val){
// execute you code here
}
});

I know this is old, but I figured I'd put this in case anyone wants an alternative. This seems ugly (at least to me) but having to deal with the way the browser handles the -1 index is what was the challenge. Yes, I know it can be done better with the jquery.data, but I'm not that familiar with that just yet.
Here is the HTML code:
<select id="selected">
<option value="1">A</option>
<option value="2">B</option>
<option value="3">C</option>
</select>
Here is the javascript code:
var currentIndex; // set up a global variable for current value
$('#selected').on(
{ "focus": function() { // when the select is clicked on
currentIndex = $('#selected').val(); // grab the current selected option and store it
$('#selected').val(-1); // set the select to nothing
}
, "change": function() { // when the select is changed
choice = $('#selected').val(); // grab what (if anything) was selected
this.blur(); // take focus away from the select
//alert(currentIndex);
//setTimeout(function() { alert(choice); }, 0);
}
, "blur": function() { // when the focus is taken from the select (handles when something is changed or not)
//alert(currentIndex);
//alert($('#selected').val());
if ($('#selected').val() == null) { // if nothing has changed (because it is still set to the -1 value, or null)
$('#selected').val(currentIndex); // set the value back to what it originally was (otherwise it will stay at what was newly selected)
} else { // if anything has changed, even if it's the same one as before
if ($('#selected').val() == 2) { // in case you want to do something when a certain option is selected (in my case, option B, or value 2)
alert('I would do something');
}
}
}
});

Something like this. Using Kevin Nadsady's above suggestion of
this.value!=this.defaultValue
I use a shared CSS class on a bunch of inputs then do:
for (var i = 0; i < myInputs.length; i++) {
myInputs[i].addEventListener('blur', function (evt) {
if(this.value!=this.defaultValue){
//value was changed now do your thing
}
});
myInputs[i].addEventListener('focus', function (evt) {
evt.target.setAttribute("value",evt.target.value);
});
}

Even if this is an old post, I thought i'd share a way to do this with simple javascript.
The javascript portion:
<script type="text/javascript">
function HideLabel(txtField){
if(txtField.name=='YOURBOXNAME'){
if(txtField.value=='YOURBOXNAME')
txtField.value = '';
else
txtField.select();
}
}
function ShowLabel(YOURBOXNAME){
if(txtField.name=='YOURBOXNAME'){
if(txtField.value.trim()=='')
txtField.value = 'YOURDEFAULTVALUE';
}
}
</script>
Now the text field in your form:
<input type="text" id="input" name="YOURBOXNAME" value="1" onfocus="HideLabel(this)"
onblur="ShowLabel(this)">
And bewn! No Jquery needed. just simple javascript. cut and paste those bad boys. (remember to put your javascript above the body in your html)

Similar to #Kevin Nadsady's post, the following will work in native JS functions and JQuery listener events. Within the onblur event, you can compare the value against the defaultValue:
$(".saveOnChange").on("blur", function () {
if (this.value != this.defaultValue) {
//Set the default value to the new value
this.defaultValue = this.value;
//todo: save changes
alert("changed");
}
});

The idea is to have a hidden field to keep the old value and whenever the onblur event happens, check the change and update the hidden value with the current text value
string html = "<input type=text id=it" + row["cod"] + "inputDesc value='"
+ row["desc"] + "' onblur =\"if (this.value != document.getElementById('hd" + row["cod"].ToString() +
"inputHiddenDesc').value){ alert('value change'); document.getElementById('hd" + row["cod"].ToString() +
"inputHiddenDesc').value = this.value; }\"> " +
"<input type=hidden id=hd" + row["cod"].ToString() + "inputHiddenDesc value='" + row["desc"] + "'>";