Develop Reference

How to get clicked button that was created dynamically?

I am trying to get a dynamically created button in order to access its parent.
I already tried to do:
var btn = document.createElement("BUTTON");
btn.innerHTML="Add";
addButton.appendChild(btn);
btn.addEventListener("click(this)", add);
sadly the button won't work if i type "click(this)". It only works if I type "click".
Changing the method to function add(element) from function add() also did not work.
How can i access the parent of my clicked button?
I cant create my buttons in HTML since i am creating a dynamic list of buttons which may differ depending on the size of the array.
Also my code should only be in Javascript
Thanks for the help!

By magic, I mean by the standard, the button reference is passed to the object.
function add() {
console.log(this);
}
var btn = document.createElement("BUTTON");
btn.innerHTML="Add";
addButton.appendChild(btn);
btn.addEventListener("click", add);
<div id="addButton"></div>
If you really wanted to pass along a variable
function add(btn, what) {
console.log(btn, what);
}
var btn = document.createElement("BUTTON");
btn.innerHTML="Add";
addButton.appendChild(btn);
btn.addEventListener("click", function(){ add(this,'foo'); });
<div id="addButton"></div>

Check this : https://www.w3schools.com/jsref/met_document_addeventlistener.asp
You should use btn.addEventListener("click", () => {}) instead of btn.addEventListener("click", () => {}).
But I think it would be better to use document.addEventListener((e) => {}) and then check the target (e.target)

jQuery nested functions

I am still new to JavaScript and jQuery, so I am confused as to why the following code is not working as I anticipated. All I am trying to do is save input on a button click (id=recordInput) and display it with another button click (id=displayInput). What I observe is that tempInput is stored, (the code works until that point) but assignment of displayInputs onclick attribute is not executed. My question is, can you not nest a $().click() call inside of another &().click() call?
<script>
$(document).ready(function () {
$('#recordInput').click(function(event) {
var tempInput = $('#testInput').val();
&('#displayInput').click(function(event) {
console.log(tempInput);
});
});
});
</script>
My thinking is this in pseudocode:
assign recordInput onclick attribute to the following function:
store tempInput
set displayInput onclick to alert the tempInput value
what is wrong with my thinking?
NOTE: I did not include any html tags but all of the ids are referenced correctly

It's not working because you have put & instead of $ here
$('#displayInput').click(function(event) {
Fixing this may work, but you shouldn't set event handlers this way. Because every time your first handler function is called it will set an event handler for the second one. You can try with your console.log and you will see that the number of console.log is increasing by every click on #recordInput. So you should better set it like this :
var tempInput;
$('#recordInput').click(function(event) {
tempInput = $('#testInput').val();
});
$('#displayInput').click(function(event) {
console.log(tempInput);
});

I would change
$(document).ready(function () {
$('#recordInput').click(function(event) {
var tempInput = $('#testInput').val();
&('#displayInput').click(function(event) {
console.log(tempInput);
});
});
});
to
$(function(){
var testInput = '';
$('#recordInput').click(function(){
testInput = $('#testInput').val();
});
$('#displayInput').click(function(){
if(testInput !== ''){
console.log(testInput);
}
});
});
You are using & instead of $. Of course, you don't have to format the code exactly like I did.

Change onclick action with a Javascript function

I have a button:
<button id="a" onclick="Foo()">Button A</button>
When I click this button the first time, I want it to execute Foo (which it does correctly):
function Foo() {
document.getElementById("a").onclick = Bar();
}
What I want to happen when I click the button the first time is to change the onclick function from Foo() to Bar(). Thus far, I've only been able to achieve an infinite loop or no change at all. Bar() would look something like this:
function Bar() {
document.getElementById("a").onclick = Foo();
}
Thus, clicking this button is just alternating which function gets called. How can I get this to work? Alternatively, what's a better way to show/hide the full text of a post? It originally starts shorted, and I provide a button to "see the full text." But when I click that button I want users to be able to click the button again to have the long version of the text go away.
Here's the full code, if it helps:
function ShowError(id) {
document.getElementById(id).className = document.getElementById(id).className.replace(/\bheight_limited\b/, '');
document.getElementById(id+"Text").className = document.getElementById(id+"Text").className.replace(/\bheight_limited\b/, '');
document.getElementById(id+"Button").innerHTML = "HIDE FULL ERROR";
document.getElementById(id+"Button").onclick = HideError(id);
}
function HideError(id) {
document.getElementById(id).className += " height_limited";
document.getElementById(id+"Text").className += " height_limited";
document.getElementById(id+"Button").innerHTML = "SHOW FULL ERROR";
document.getElementById(id+"Button").onclick = "ShowError(id)";
}

Your code is calling the function and assigning the return value to onClick, also it should be 'onclick'. This is how it should look.
document.getElementById("a").onclick = Bar;
Looking at your other code you probably want to do something like this:
document.getElementById(id+"Button").onclick = function() { HideError(id); }

var Foo = function(){
document.getElementById( "a" ).setAttribute( "onClick", "javascript: Boo();" );
}
var Boo = function(){
alert("test");
}

Do not invoke the method when assigning the new onclick handler.
Simply remove the parenthesis:
document.getElementById("a").onclick = Foo;
UPDATE (due to new information):
document.getElementById("a").onclick = function () { Foo(param); };

Thanks to João Paulo Oliveira, this was my solution which includes a variable (which was my goal).
document.getElementById( "myID" ).setAttribute( "onClick", "myFunction("+VALUE+");" );

I recommend this approach:
Instead of having two click handlers, have only one function with a if-else statement. Let the state of the BUTTON element determine which branch of the if-else statement gets executed:
HTML:
<button id="a" onclick="toggleError(this)">Button A</button>
JavaScript:
function toggleError(button) {
if ( button.className === 'visible' ) {
// HIDE ERROR
button.className = '';
} else {
// SHOW ERROR
button.className = 'visible';
}
}
Live demo: http://jsfiddle.net/simevidas/hPQP9/

You could try changing the button attribute like this:
element.setAttribute( "onClick", "javascript: Boo();" );

What might be easier, is to have two buttons and show/hide them in your functions. (ie. display:none|block;) Each button could then have it's own onclick with whatever code you need.
So, at first button1 would be display:block and button2 would be display:none. Then when you click button1 it would switch button2 to be display:block and button1 to be display:none.

For anyone, like me, trying to set a query string on the action and wondering why it's not working-
You cannot set a query string for a GET form submission, but I have found you can for a POST.
For a GET submission you must set the values in hidden inputs e.g.
an action of: "/handleformsubmission?foo=bar"
would have be added as the hidden field like: <input type="hidden" name="foo" value="bar" />
This can be done add dynamically in JavaScript as (where clickedButton is the submitted button that was clicked:
var form = clickedButton.form;
var hidden = document.createElement("input");
hidden.setAttribute("type", "hidden");
hidden.setAttribute("name", "foo");
hidden.setAttribute("value", "bar");
form.appendChild(hidden);
See this question for more info
submitting a GET form with query string params and hidden params disappear

By JQuery, how to specify on function as onClick handler for many radio buttons?

I have a function called handleOnClickRadio(i, j); and lots of radio buttons named as id="something-radio[i][j]". All these radio buttons are in a table called "bigtable".
How could I attach the function handleOnClickRadio() to all these radio buttons? And call it correct with handleOnClickRadio(i,j).
Thanks.

I would not attach the click handler to the buttons at all. You say you have lots of them. Attaching the same event handler to each of them is a waste of memory and could even be a performance problem.
Use event delegation instead:
$('#tableID').delegate('input[type=radio]', 'click', function() {
// code here
});
Then you could extract the i and j via regular expression (you could also consider to change the pattern so that you can use something simpler like split()):
var exp = new RegExp("\\[(.+?)\\]\\[(.+?)\\]", 'g');
var match = exp.exec(this.id);
var i = match[1];
var j = match[2];
You could put this together like so:
$('#tableID').delegate('input[type=radio]', 'click', function() {
var match = this.id.match(/\[(.+?)\]\[(.+?)\]/)
var i = match[1]; // use parseInt(match[1]) if you need an integer
var j = match[2];
handleOnClickRadio(i,j);
});
edit: Made code a bit simpler.
If i and j correspond to column and row indicies, see #Caspar Kleijne's answer for an alternative way to retrieve them.
For accessibility, you should consider binding the handler to the change event. Then changes via the keyboard will be recognized too.

wire up the event like this
$("#bigtable input[type='radio']").bind("click", OnClickRadio);
and use the handler like
var OnClickRadio = function () {
var col = $(this).parent("td").index();
var row = $(this).parent("td").parent("tr").index();
handleOnClickRadio(col, row)
});

You can attach an onClick method to a collection of radio buttons within a table with a simple bit of jQuery. When you say 'table called "bigtable"', I'm assuming that you mean that it has id="bigtable" in the following code.
$(document).ready(function() {
$("#bigtable input:radio").click(function() {
// Your on click code here
});
});
However, I would usually give each of the radio buttons a specific class using class="magicRadioButton" and then your jQuery code becomes a little clearer and doesn't rely on all of those radio buttons being within a table;
$(document).ready(function() {
$(".magicRadioButton").click(function() {
// Your on click code here
});
});
Now, if you need to then plug this information into your current handleOnClickRadio method, you can do so with the following.
$(document).ready(function() {
$("#bigtable input:radio").click(function() {
var button_id = $(this).attr("id");
var re = new RegExp("\\[(.*?)\\]\\[(.*)\\]");
var matches = re.exec(button_id);
var i = matches[1];
var j = matches[2];
handleOnClickRadio(i,j);
});
});

Give them class names in conjunction with $(this) in your click trigger

I suggest using delegate if you have lot of radios: that way, only one Event listener will be attached
see http://api.jquery.com/delegate/
$("#globalContainer").delegate("input", "click", function(){
//Perform a string test / regex to test if the id matches something-radio[i][j]
//With a regex with capturing groups you can retrieve [i] and [j] values at the same time
if ( test($(this).attr("id")) ) {
}
});

Ideally, you'd have a onclick assigned to the big table rather than each and every radio button. Events in JavaScript bubble up so the table (which is the eventual parent of all these radio buttons) will receiving the event.
So in jQuery you would have code like this
$('#bigtable').click(handleOnClickRadio);
The signature of your handleOnClickRadio function would be
function handleOnClickRadio(evt) {
var radio = evt.target;
var id = $(radio).attr('id');
}
evt.target will identify the actual radio button that was clicked/checked and you can access other attributes of the radio as well. such as
$(radio).attr('id)
Will give you the id of the radio button.

<input type="radio" class="many-radio-buttons" ....
jQuery:
$('.many-radio-buttons').click(function() {
//your_code;
});

How can I add an onclick handler on a dynamic element?

Here is the important part of my JS code:
function createClose() {
var cButton = document.createElement("img");
cButton.src = "close.gif";
cButton.style.cursor = "pointer";
cButton.onclick = closeWindow;
document.getElementById("my_window").appendChild(cButton);
}
function closeWindow() {
document.getElementById("my_window").style.display = "none";
}
The image gets created and appended, but there is no onClick event invoked when it is clicked. I also tried using an anonymous function, but that didn't work either.
No, I'm not going to use jQuery (although I believe you that it's easier).

input.setAttribute('onclick','handleClick();');

input = document.getElementById("my_window").appendChild(cButton);
input.onclick = function() { yourFunction(); };
This question is almost a duplicate of "Add onclick property to input with JavaScript"
As an alternative way I've seen the use of input.setAttribute('onclick', 'yourFunction();'); too but cannot guarantee it works.