Develop Reference

how do I pass a variable to a function that is attached to an event handler and also prevent default in javascript?

I am writing a function for autofill, which will display a list of values to select as potential value input. The names of the input fields are dynamic so I need to pass that to the function that is executed by the event handler, but I also need to prevent default button action. The error that I've been getting is that the passed targetField gets seen as the event and I have not been able to figure out how to fix this. Would appreciate some help. This is what I have now.
function dropdownList(testlist, clicked) {
const listEl = document.createElement("ul");
listEl.classname = "autocomplete-list";
testlist.forEach(item => {
const listItem = document.createElement("li");
const valueButton = document.createElement("button");
valueButton.innerHTML = item
valueButton.addEventListener("click", valueSelect(targetField);
listItem.appendChild(valueButton);
listEl.appendChild(listItem)
})
let clickedId = `scripts-${clicked}-script`
let targetField = document.querySelector("[data-testid=" + clickedId + "]")
document.querySelector("[data-testid=" + clickedId + "]").after(listEl)
valueSelect(targetField);
}
function valueSelect(targetField) {
event.preventDefault();
const buttonEl = event.target;
targetField.value = buttonEl.innerHTML
}

This code works. Your problem was mostly with the eventListener, and with the parameters of the valueSelect function.
Note: I changed your clicked variable to be the actual element, not the element's id
document.querySelector("#myInput").addEventListener("click", (event)=>dropdownList(["a", "b", "c"], event.target))
function dropdownList(testlist, clicked) {
const listEl = document.createElement("ul");
listEl.classname = "autocomplete-list";
testlist.forEach(item => {
const listItem = document.createElement("li");
const valueButton = document.createElement("button");
valueButton.innerHTML = item
valueButton.addEventListener("click", (event)=>valueSelect(event, clicked));
listItem.appendChild(valueButton);
listEl.appendChild(listItem)
})
clicked.after(listEl)
}
function valueSelect(event, targetField) {
event.preventDefault();
const buttonEl = event.target;
targetField.value = buttonEl.innerHTML
}
<label>Test</label><input type="text" id="myInput" />

Remove dynamically created elements by class name Javascript

So, in plain terms I am creating a Chrome Extension that so far can only save links from the internet but not delete them. What I want to add is a "remove" button for deleting unwanted links. So far I haven't got that to work.
The buttons I want to remove are added using JavaScript. Each new block of HTML features a "remove" button but clicking that button does nothing. I have tried binding listeners to each element using a for loop but that doesn't seem to work.
The code runs without errors and I'm certain that the issue is a slight oversight but I have only just started using JavaScript so I'm lost for solutions at the moment.
I have included all the code because I don't want to leave out anything that might be imperative to finding a solution.
It starts with the code for adding a link, followed by removing a single link and then removing all links at once. Thank you all for any help, really want to get this working.
https://github.com/mmmamer/Drop Repository for the rest of the code. Mainly popup.html and popup.css.
var urlList = [];
var i = 0;
document.addEventListener('DOMContentLoaded', function() {
getUrlListAndRestoreInDom();
// event listener for the button inside popup window
document.getElementById('save').addEventListener('click', addLink);
});
function addLink() {
var url = document.getElementById("saveLink").value;
addUrlToListAndSave(url);
addUrlToDom(url);
}
function getUrlListAndRestoreInDom() {
chrome.storage.local.get({
urlList: []
}, function(data) {
urlList = data.urlList;
urlList.forEach(function(url) {
addUrlToDom(url);
});
});
}
function addUrlToDom(url) {
// change the text message
document.getElementById("saved-pages").innerHTML = "<h2>Saved pages</h2>";
var newEntry = document.createElement('li');
var newLink = document.createElement('a');
var removeButton = document.createElement('button');
removeButton.textContent = "Remove";
//removeButton.createElement('button');
removeButton.type = "button";
removeButton.className = "remove";
newLink.textContent = url;
newLink.setAttribute('href', url);
newLink.setAttribute('target', '_blank');
newEntry.appendChild(newLink)
newEntry.appendChild(removeButton);
newEntry.className = "listItem";
document.getElementById("list").appendChild(newEntry);
}
function addUrlToListAndSave(url) {
urlList.push(url);
saveUrlList();
//}
}
function saveUrlList(callback) {
chrome.storage.local.set({
urlList
}, function() {
if (typeof callback === 'function') {
//If there was no callback provided, don't try to call it.
callback();
}
});
}
// remove a single bookmark item
document.addEventListener('DOMContentLoaded', function() {
getUrlListAndRestoreInDom();
var allButtons = document.getElementsByClassName('remove');
function listenI(i) {
allButtons[i].addEventListener('click', () => removeMe(i));
}
for (var i = 0; i < allButtons.length; i++) {
listenI(i);
}
});
function removeMe(i) {
var fullList = documents.getElementsByClassName('listItem');
listItem[i].parentNode.removeChild(listItem[i]);
}
//remove all button
document.addEventListener('DOMContentLoaded', function() {
document.getElementById("remove-all").addEventListener('click', function() {
var removeList = document.getElementsByClassName("listItem");
while(removeList[0]) {
removeList[0].parentNode.removeChild(removeList[0]);
}
})
});

chrome.storage.local.get() is asynchronous. So when you try to add the event listeners to the Remove buttons, they're not in the DOM yet.
You can add the listener in the addUrlToDom() function instead. That way you'll also add the event listener when you create new buttons.
function addUrlToDom(url) {
// change the text message
document.getElementById("saved-pages").innerHTML = "<h2>Saved pages</h2>";
var newEntry = document.createElement('li');
var newLink = document.createElement('a');
var removeButton = document.createElement('button');
removeButton.textContent = "Remove";
//removeButton.createElement('button');
removeButton.type = "button";
removeButton.className = "remove";
newLink.textContent = url;
newLink.setAttribute('href', url);
newLink.setAttribute('target', '_blank');
newEntry.appendChild(newLink)
newEntry.appendChild(removeButton);
removeButton.addEventListener("click", function() {
var anchor = this.previousElementSibling;
var url = anchor.getAttribute("href");
removeUrlAndSave(url);
this.parentNode.remove();
});
newEntry.className = "listItem";
document.getElementById("list").appendChild(newEntry);
}
function removeUrlAndSave(url) {
var index = urlList.indexOf(url);
if (index != -1) {
urlList.splice(index, 1);
saveUrlList();
}
}

onclick excecutes does not work, only when creating DOM

I have the following HTML and javascript.
I can create the buttons without any problem, but the onclick function does not work when clicking the button. It does not do anything.
If I put the method without the ' it excecutes when generating the form, one after the other generating 3 dialogs
function makeUL(array) {
var list = document.createElement('ul');
for (var i = 0; i < array.length; i++) {
var btn = document.createElement("BUTTON");
/*
btn.onClick = function () {
buttonClicked(array[i]);
};*/
var t = document.createTextNode(array[i]); // Create a text node
btn.appendChild(t); // Append the text to <button>
btn.type = "button"
btn.onClick = 'buttonClicked()';
list.appendChild(btn); // Append <button> to <body>
var nextLine = document.createElement("td");
list.appendChild(nextLine);
}
return list;
}
/*
function buttonClicked(buttonName){
alert(buttonName);
}*/
function buttonClicked() {
alert("algo");
}
self.onInit = function() {
var boton = [];
for (var g = 0; g < self.ctx.settings.Botones.length; g++) {
boton[0] = self.ctx.settings.Botones[g].btnId;
boton[1] = self.ctx.settings.Botones[g].method;
boton[2] = self.ctx.settings.Botones[g].params;
document.getElementById('myList').appendChild(makeUL(boton));
}
self.ctx.$scope.sendCommand = function() {
var timeout = self.ctx.settings.requestTimeout;
var rpcMethod = self.ctx.settings.method;
var rpcParams = self.ctx.settings.params;
var commandPromise;
commandPromise = self.ctx.controlApi.sendTwoWayCommand(rpcMethod, rpcParams, timeout);
commandPromise.then(
function success(response) {
//alert("Comando recibido exitosamente\n Respuesta:" + angular.toJson(response));
alert("Comando recibido exitosamente");
},
function fail(rejection) {
alert("ERROR AL ENVIAR COMANDO");
}
);
};
};
<form name="rpcForm">
<md-content class="md-padding" layout="column">
<div id="myList"></div>
</md-content>
</form>

The problem is:
btn.onClick = 'buttonClicked()';
It looks like you were trying to assign to the onclick attribute of the HTML, in which case the proper syntax would be
btn.setAttribute('onclick', 'buttonClicked()');
But since you already have a reference to the element, there's no need to resort to attributes; inline handlers are pretty bad practice anyway. Change to:
btn.onclick = buttonClicked;
(note the lower-case c in onclick), or
btn.addEventListener('click', buttonClicked);
Also, you might consider simply assigning to the button's textContent rather than creating a text node explicitly, it's a bit easier to read and write: change
var t = document.createTextNode(array[i]); // Create a text node
btn.appendChild(t); // Append the text to <button>
to
btn.textContent = array[i];

How to call javascript function only once during window.onscroll event?

function getH4() {
var xyz = document.getElementsByClassName('bucket_left');
for(var i=0;i<xyz.length;i++){
var x=document.getElementsByTagName("h4")[i].innerHTML;
var current_bucket = xyz[i];
var y=current_bucket.firstChild.href;
var newdiv = document.createElement('div');
newdiv.innerHTML = ""+x+"";
newdiv.className = "hover_title_h4";
current_bucket.appendChild(newdiv);
}
}
window.onscroll=getH4;
In above code i want to append new div in set of divs having class bucket_left and this divs generated from infinite scrolling. above code is working fine but on scroll it appends so many divs.
so how do i append only once ?

Add the following line at the end of your function:
function getH4() {
// ...
window.onscroll = null;
}

create a global boolean variable and set it to false. again set it to true in the window scroll event and chk the variable is false using a if block. put your code inside that if block.
var isScrolled = false;
function getH4() {
if(!isScrolled){
//your code
}
isScrolled = true
}

You only have to set the onscroll property to none as following at the end of you JavaScript function:
window.onscroll = null;
Now when the script executes for the first time, it will perform its function and the above line will set the onscroll to null and thus will not invoke any event on scroll of your mouse and so your function wont be invoked again and again on the event except for the first time.
Or you could handle it logically by setting a public var say var check = 0 and then set the variable to 1 when entered for the first time. So you need to check the value of check and based on that execute the function
var check = 1;
function getH4() {
if(check==1)
{
var xyz = document.getElementsByClassName('bucket_left');
for(var i=0;i<xyz.length;i++){
var x=document.getElementsByTagName("h4")[i].innerHTML;
var current_bucket = xyz[i];
var y=current_bucket.firstChild.href;
var newdiv = document.createElement('div');
newdiv.innerHTML = ""+x+"";
newdiv.className = "hover_title_h4";
current_bucket.appendChild(newdiv);
}
check=0;
}
}

you can try this:
when scrolling,the check equal false, and the append event will happen just once;
when the scroll end(mouseup or mouseout), the check equal true, you can append again.
var check = true;
function getH4(event) {
event.target.onmouseup = function() {
check = true;
}
event.target.onmouseout = function() {
check = true;
}
if (check) {
var xyz = document.getElementsByClassName('bucket_left');
for(var i=0;i<xyz.length;i++){
var x=document.getElementsByTagName("h4")[i].innerHTML;
var current_bucket = xyz[i];
var y=current_bucket.firstChild.href;
var newdiv = document.createElement('div');
newdiv.innerHTML = ""+x+"";
newdiv.className = "hover_title_h4";
current_bucket.appendChild(newdiv);
}
check = false;
}
window.onscroll=getH4

trying to remove and store and object with detach()

I am trying to remove an object and store it (in case a user wants to retrieve it later). I have tried storing the object in a variable like it says in the thread below:
How to I undo .detach()?
But the detach() does not remove the element from the DOM or store it. I am also not getting any error messages. Here is the code I am using to detach the element:
function MMtoggle(IDnum) {
var rowID = "row" + IDnum;
var jRow = '#' + rowID;
thisMMbtn = $(jRow).find(".addMMbtn");
var light = false;
var that = this;
if (light == false) {
thisMMbtn.bind("click",
function() {
var thisRow = $(this).closest(".txtContentRow");
var thisTxt = thisRow.find(".txtContent");
var cellStr = '<div class = "mmCell prep"></div>';
$(cellStr).appendTo(thisTxt);
$(this).unbind("click");
light = true;
}
);
}
else {
thisMMbtn.bind("click",
function() {
var thisRow = $(this).closest(".txtContentRow");
thisMM = thisRow.find(".mmCell");
SC[rowID].rcbin = thisMM.detach(); //here is where I detach the div and store it in an object
$(this).unbind("click");
light = false;
}
);
}
}
MMtoggle(g.num);
A fiddle of the problem is here: http://jsfiddle.net/pScJc/
(the button that detaches is the '+' button on the right. It is supposed to add a div and then detach it when clicked again.)

Looking at your code I don't think so you need detach for what you are trying to achieve.
Instead try this code.
thisMMbtn.bind("click",
function() {
var thisRow = $(this).closest(".txtContentRow");
var thisTxt = thisRow.find(".txtContent");
var $mmCell = thisTxt.find('.mmCell');
if($mmCell.length == 0){
$mmCell = $('<div class = "mmCell prep"></div>')
.appendTo(thisTxt).hide();
}
$mmCell.toggle();
//$(this).unbind("click");
}
);
Demo