Develop Reference

When to Call JavaScript Toggle Function?

I have a drop down menu I need to make appear and disappear using pure JavaScript (no libraries/jQuery). Thus I am developing a toggle function. However despite trying several approaches, nothing seems to work. My current idea is to create a variable to hold the state of the menu (open or closed). Once the display of the menu changes from "none" to "block", the variable should change from "closed" to "open". Then an event listener would be added to the body element so when anything is clicked, the menu closes (i.e. the display property is changed back to "none").
Unfortunately the above doesn't seem work. When I put the If/else block outside of an event listener it fires when the page loads, but not when the menuToggle variable changes. If I put it or a function inside the menuPlaceholder event listener the menu won't open, probably due to the open and close code being called basically at the same time.
Clearly I am missing something, probably related to program control or function calling. Does anyone have any insights?
The code I am working with is below. Note the alert functions peppered throughout the code are for testing purposes only.
//Puts IDs for search preference selection box into variables
var menuPlaceholder = document.getElementById('searchSelection');
var menuDisplay = document.getElementById('searchOptions');
var boxLabel = document.getElementById('searchLabel');
//Puts IDs for text input box and submission into variables
var searchBoxPlaceholder = document.getElementById('searchInput');
var searchInput = document.getElementById('searchBox');
var submitButton = document.getElementById('submit');
//Adds class to each search option and puts ID of hidde field into variable
var searchPrefSubmission = document.getElementsByClassName('buttonSearch');
var hiddenInput = document.getElementById('searchChoice');
//Global variable to indicate whether searchOptions menu is opened or closed
var menuToggle = "closed";
//Closes element when one clicks outside of it.
function hideOnClickOutside(element) {
const outsideClickListener = event => {
if (!element.contains(event.target) && isVisible(element)) { // or use: event.target.closest(selector) === null
element.style.display = 'none'
removeClickListener()
}
}
const removeClickListener = () => {
document.removeEventListener('click', outsideClickListener)
}
document.addEventListener('click', outsideClickListener)
}
const isVisible = elem => !!elem && !!( elem.offsetWidth || elem.offsetHeight || elem.getClientRects().length )
//When the placeholder box is clicked, the option menu appears
menuPlaceholder.addEventListener('click', function (event){
menuDisplay.style.display = "block";
menuToggle = "open";
//Add click event to searchPref buttons
for (i = 0; i < searchPrefSubmission.length; i++) {
//Assigns value of the button to both the hidden input field and the placeholder box
searchPrefSubmission[i].addEventListener('click', function(event) {
hiddenInput.value=this.value;
boxLabel.innerHTML = this.value;
menuDisplay.style.display = "none";
menuPlaceholder.style.display = "inline-block";
});
}
});
//This code causes the text input box of the search form to appear when the background box is clicked
searchBoxPlaceholder.addEventListener('click', function(event){
searchInput.style.display = "inline";
submitButton.style.display = "inline";
//hideOnClickOutside(menuDisplay);
});
if (menuToggle == "open"){
document.body.addEventListener('click', function(event){
alert('Foo!');
})
}else{
alert('Boo!');
}
/*function toggleMenu () {
//menuDisplay.style.display = "none";
alert('Boo!');
menuToggle = "closed";
}*/
body {
font-family:Montserrat, sans-serif;
}
#searchOptionPlaceholder {
display: inline-block;
}
#searchSelection {
padding: 10px 20px;
margin-right: 10px;
background-color: #F0F3F5;
display: inline-block;
color: #000000;
width: 140px;
max-width: 200px;
max-height: 35px;
border: 2px solid black;
vertical-align: middle;
}
#searchSelection img {
float: right;
}
#searchLabel {
display: inline-block;
padding-top: 10px;
vertical-align: top;
}
#searchOptions {
display: none;
background-color: #F0F3F5;
position: absolute;
z-index: 2;
}
#searchOptions ul {
background-color: #F0F3F5;
padding: 5px;
}
#searchOptions li {
list-style-type: none;
border-bottom: 2px solid black;
}
#searchOptions li:hover {
background-color: #706868;
color: #ffffff;
}
.buttonSearch {
background-color: transparent;
border: none;
padding: 10px;
font-size: 14px;
}
.searchSubHeading {
font-size: 12px;
}
#searchInput {
display: inline-block;
background-color: #F0F3F5;
padding: 10px 100px;
position: relative;
top: 0px;
max-width: 350px;
border: 2px solid black;
vertical-align: middle;
}
#searchInput img {
position: relative;
left: 80px;
}
#searchBox {
display: none;
width: 80%;
background-color: #F0F3F5;
border: none;
font-size: 1.5em;
position: relative;
right: 50px;
vertical-align: middle;
}
#submit {
border: none;
background-image: url('https://library.domains.skidmore.edu/search/magnifyingGlass.png');
background-repeat: no-repeat;
background-size: contain;
width: 50px;
height: 30px;
position: relative;
right: -80px;
vertical-align: middle;
}
#otherLinks {
margin-top: 10px;
}
#otherLinks a{
color: #000000;
}
#otherLinks a:hover{
color: #006a52;
}
<h1>Library Search</h1>
<form method="post" action="https://library.domains.skidmore.edu/search/searchBox.php" id="librarySearch">
<div id="searchSelection"><span id="searchLabel">Catalog</span><img src="down.png" height="30px" width="30px" /></div>
<div id="searchOptions">
<ul>
<li><button type="button" name="searchPref" value="Catalog" class="buttonSearch">Catalog<br /><br /><span class="searchSubHeading">Search books and DVDs</span></button></li>
<li><button type="button" name="searchPref" value="SearchMore" class="buttonSearch">SearchMore<br /><br /><span class="searchSubHeading">Search everything</span></button></li>
<li><button type="button" name="searchPref" value="Journals" class="buttonSearch">Journals<br /><br /><span class="searchSubHeading">Search journals</span></button></li>
</ul>
</div>
<div id="searchInput">
<input type="hidden" id="searchChoice" name="searchPref" value="catalog" />
<input type="search" id="searchBox" size="60" name="searchText" placeholder="Search our holdings"/><button type="submit" id="submit"></button></div>
<div id="otherLinks">Advanced Catalog Search | WorldCat | eBooks</div>
</form>

Some issues:
Adding event listeners within an event listener is in most cases a code smell: this will add those inner listeners each time the outer event is triggered. Those listeners remain attached, and so they accumulate. So, attach all event handlers in the top-level script, i.e. on page load, and then never again.
The if ... else at the end will execute on page load, and then never again. So the value of menuToggle is guaranteed to be "closed". You need to put that if...else switch inside the handler, so that it executes every time the event triggers, at which time the menuToggle variable will possibly have a modified value.
The body element does not stretch (by default) over the whole window. If you want to detect a click anywhere on the page, you should attach the listener on the document element itself, not on document.body.
When the click on the menu placeholder is handled, you should avoid that this event "bubbles" up the DOM tree up to the document, because there you have the other handler that wants to hide the menu again. You can do this with event.stopPropagation().
The global variable is not absolutely necessary, but if you use it, then I would call it menuVisible and give it a boolean value: false at first, and possibly true later.
For actually toggling the menu, I would create a function, which takes the desired visibility (false or true) as argument, and then performs the toggle.
Do not use undeclared variables, like the for loop variable i. Define it with let.
Here is your code with those changes implemented. Of course, there is still a lot that could be improved, but I believe that goes beyond the scope of this question:
var menuPlaceholder = document.getElementById('searchSelection');
var menuDisplay = document.getElementById('searchOptions');
var boxLabel = document.getElementById('searchLabel');
var searchBoxPlaceholder = document.getElementById('searchInput');
var searchInput = document.getElementById('searchBox');
var submitButton = document.getElementById('submit');
var searchPrefSubmission = document.getElementsByClassName('buttonSearch');
var hiddenInput = document.getElementById('searchChoice');
// Changed name and type of global variable:
var menuVisible = false;
// Removed some functions ...
menuPlaceholder.addEventListener('click', function (event){
// Use new function for actually setting the visibility
toggleMenu(!menuVisible);
// Avoid that click event bubbles up to the document level
event.stopPropagation();
});
// Add these event handlers on page load, not within another handler
// Define loop variable with let
for (let i = 0; i < searchPrefSubmission.length; i++) {
//Assigns value of the button to both the hidden input field and the placeholder box
searchPrefSubmission[i].addEventListener('click', function(event) {
hiddenInput.value = this.value;
boxLabel.innerHTML = this.value;
// Use the new function for setting the visibility
toggleMenu(false);
menuPlaceholder.style.display = "inline-block";
});
}
searchBoxPlaceholder.addEventListener('click', function(event){
searchInput.style.display = "inline";
submitButton.style.display = "inline";
});
// Bind handler on document itself, and call new function
document.addEventListener('click', function(event) {
toggleMenu(false);
});
// new function to perform the toggle
function toggleMenu(show) {
menuDisplay.style.display = show ? "block" : "none";
menuVisible = show;
}
body {
font-family:Montserrat, sans-serif;
}
#searchOptionPlaceholder {
display: inline-block;
}
#searchSelection {
padding: 10px 20px;
margin-right: 10px;
background-color: #F0F3F5;
display: inline-block;
color: #000000;
width: 140px;
max-width: 200px;
max-height: 35px;
border: 2px solid black;
vertical-align: middle;
}
#searchSelection img {
float: right;
}
#searchLabel {
display: inline-block;
padding-top: 10px;
vertical-align: top;
}
#searchOptions {
display: none;
background-color: #F0F3F5;
position: absolute;
z-index: 2;
}
#searchOptions ul {
background-color: #F0F3F5;
padding: 5px;
}
#searchOptions li {
list-style-type: none;
border-bottom: 2px solid black;
}
#searchOptions li:hover {
background-color: #706868;
color: #ffffff;
}
.buttonSearch {
background-color: transparent;
border: none;
padding: 10px;
font-size: 14px;
}
.searchSubHeading {
font-size: 12px;
}
#searchInput {
display: inline-block;
background-color: #F0F3F5;
padding: 10px 100px;
position: relative;
top: 0px;
max-width: 350px;
border: 2px solid black;
vertical-align: middle;
}
#searchInput img {
position: relative;
left: 80px;
}
#searchBox {
display: none;
width: 80%;
background-color: #F0F3F5;
border: none;
font-size: 1.5em;
position: relative;
right: 50px;
vertical-align: middle;
}
#submit {
border: none;
background-image: url('https://library.domains.skidmore.edu/search/magnifyingGlass.png');
background-repeat: no-repeat;
background-size: contain;
width: 50px;
height: 30px;
position: relative;
right: -80px;
vertical-align: middle;
}
#otherLinks {
margin-top: 10px;
}
#otherLinks a{
color: #000000;
}
#otherLinks a:hover{
color: #006a52;
}
<h1>Library Search</h1>
<form method="post" action="https://library.domains.skidmore.edu/search/searchBox.php" id="librarySearch">
<div id="searchSelection">
<span id="searchLabel">Catalog</span>
<img src="down.png" height="30px" width="30px" />
</div>
<div id="searchOptions">
<ul>
<li>
<button type="button" name="searchPref" value="Catalog" class="buttonSearch">
Catalog<br /><br /><span class="searchSubHeading">Search books and DVDs</span>
</button>
</li>
<li>
<button type="button" name="searchPref" value="SearchMore" class="buttonSearch">
SearchMore<br /><br /><span class="searchSubHeading">Search everything</span>
</button>
</li>
<li>
<button type="button" name="searchPref" value="Journals" class="buttonSearch">
Journals<br /><br /><span class="searchSubHeading">Search journals</span>
</button>
</li>
</ul>
</div>
<div id="searchInput">
<input type="hidden" id="searchChoice" name="searchPref" value="catalog" />
<input type="search" id="searchBox" size="60" name="searchText" placeholder="Search our holdings"/>
<button type="submit" id="submit"></button>
</div>
<div id="otherLinks">
Advanced Catalog Search |
WorldCat |
eBooks
</div>
</form>

How to position a h1 directly over an input and have it be for all screens?

So I want to replace the text inside of an input field with a h1 tag as soon as the user hits submit because i want the text to have an animation but i can't animate the text inside the text field.
I linked the code pen project version of it to make it easier then organizing all the code in here. I added all the code I had so I wouldn't leave anything out although some of it may be irrelevant.
Basically I want the h1 tag to appear exactly where the input text was so it looks like nothing ever got replaced.
https://codepen.io/timvancowabunga/pen/rNOqdYd
$(document).ready(function() {
$('#btn1').click(function() {
$('#test').text($("#message").val());
$('#message').val('');
$('#test').val('');
});
});
function onTextClick() {
document.getElementById('btn1').className = "show";
}
function showButton() {
document.getElementById('btn1').style.display = 'block';
}
function showSendButton() {
document.getElementById('btn2').style.display = 'block';
}
function formCheck() {
var input = $('#message').val();
if (input == '') {
alert("Please Submit a Valid Message");
} else {
hideButton();
showSendButton();
}
}
function hideButton() {
document.getElementById('btn1').style.display = 'none';
}
function hideSendButton() {
document.getElementById('btn2').style.display = 'none';
document.getElementById('sent').style.display = 'block';
}
function myMove() {
var textWrapper = document.querySelector('.ml13');
textWrapper.innerHTML = textWrapper.textContent.replace(/\S/g, "<span class='letter'>$&</span>");
anime.timeline()
.add({
targets: '.ml13 .letter',
translateY: [0, -1600],
opacity: [1, 0],
easing: "easeInSine",
duration: 3600,
delay: (el, i) => 800 + 60 * i
});
}
body {
background-color: #368670;
font-family: sans-serif;
}
.ml13,
.ml14,
.ml15 {
font-size: 1.9em;
text-transform: uppercase;
letter-spacing: 0.2em;
font-weight: 600;
}
.ml15 {
letter-spacing: 0em;
text-align: center;
}
.ml13 .letter {
display: inline-block;
line-height: 1em;
}
.line {
display: flex;
margin: auto;
width: 50%;
margin-top: 500px;
}
.wrappy {
position: relative;
}
.wrappy h1 {
position: absolute;
left: 48.5%;
top: 20%
}
.butt {
padding-top: 50px;
display: flex;
margin: 0 auto;
width: 100%;
}
#btn1,
#btn2 {
display: table;
margin: 0 auto;
}
input {
z-index: 1000;
margin-left: 10%;
width: 80%;
background: transparent;
border: 0;
border-bottom: 1px solid;
padding: 1em 0 .1em;
text-align: center;
font-size: 18px;
font-family: inherit;
font-weight: 300;
line-height: 1.5;
color: inherit;
outline: none;
}
input:focus {
border-color: #ffffff;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/animejs/2.0.2/anime.min.js"></script>
<div class="truth">
<!-- <div class="line"> -->
<div class="message-box">
<form class="message-form">
<h2 class="ml15" for="message">TELL A TRUTH</h2>
<div class="wrappy">
<input type="text" id="message" name="message" autocomplete="off" class="ml14">
<!-- <h1 id="test" class="ml13">I love your music!</h1> -->
<h1 id="test" class="ml13"></h1>
</div>
</form>
</div>
<div class="butt">
<button id="btn1" onclick="formCheck();">Ready to Send?</button>
<button id="btn2" style="display: none" onclick="myMove(); setTimeout(showButton, 3000); hideSendButton();">Send!</button>
</div>
</div>

You want to put H1 below the input.
Then you make the text input transparent. Bind the input value to h1.
So in effect when user clicks and type, they are selecting the input and changing its value, but it's transparent, to be shown by the h1 below the input that you will eventually animate.
Also because you mentioned you want it to display correctly in all platforms. You then have to be cognisant of the default behaviours of DOM and CSS properties. If you alter them to get what you want without knowing its natural order, you can get unexpected behaviour and reduce cross-browser compatibility. I have made changes to reflect that.
$(document).ready(function () {
$("#btn1").click(function () {
$("#test").text($("#message").val());
$("#message").val("");
$("#test").val("");
});
});
function onTextClick() {
document.getElementById("btn1").className = "show";
}
function showButton() {
document.getElementById("btn1").style.display = "block";
}
function showSendButton() {
document.getElementById("btn2").style.display = "block";
}
function formCheck() {
var input = $("#message").val();
if (input == "") {
alert("Please Submit a Valid Message");
} else {
hideButton();
showSendButton();
}
}
function hideButton() {
document.getElementById("btn1").style.display = "none";
}
function hideSendButton() {
document.getElementById("btn2").style.display = "none";
document.getElementById("sent").style.display = "block";
}
// attach this to bind h1 to the input value at all times.
$("#message").keyup(function () {
var self = this;
$("#test").text($(this).val());
});
function myMove() {
var textWrapper = document.querySelector(".ml13");
textWrapper.innerHTML = textWrapper.textContent.replace(
/\S/g,
"<span class='letter'>$&</span>"
);
anime.timeline().add({
targets: ".ml13 .letter",
translateY: [0, -1600],
opacity: [1, 0],
easing: "easeInSine",
duration: 3600,
delay: (el, i) => 800 + 60 * i
});
}
body {
background-color: #368670;
font-family: sans-serif;
}
.ml13,
.ml14,
.ml15 {
font-size: 1.9em;
text-transform: uppercase;
letter-spacing: 0.2em;
font-weight: 600;
}
.ml15 {
letter-spacing: 0em;
text-align: center;
}
.ml13 .letter {
display: inline-block;
line-height: 1em;
}
.line {
display: flex;
margin: auto;
width: 50%;
margin-top: 500px;
}
.wrappy {
position: relative;
text-align: center;
}
.wrappy h1 {
position: absolute; /* you then want to give wrappy h1 this to make it occupy no space. */
width: 100%; /* to centralize the text, your option here is to make this 100% width and use text-align */
text-align: center;
padding-top: 21px;
}
.butt {
padding-top: 50px;
display: flex;
margin: 0 auto;
width: 100%;
}
#btn1,
#btn2 {
display: table;
margin: 0 auto;
}
input {
position: relative; /* in order for z-index to work, you need to give an element `position` attribute of value `static`, `relative` or `absolute`. */
z-index: 1000; /* now this will work. wrappy h1 is not given a `z-index` so it defaults to `1`, hence input will be on top of wrappy h1 now. */
width: 80%;
background: transparent;
border: 0;
border-bottom: 1px solid #000; /* you need the line back because we are going to assign color to be transparent */
padding: 35px 0 0 0;
text-align: center;
font-size: 18px;
font-family: inherit;
font-weight: 300;
line-height: 1.5;
color: transparent; /* make the text transparent */
outline: none;
}
input:focus {
border-color: #ffffff;
}
<div class="truth">
<!-- <div class="line"> -->
<div class="message-box">
<form class="message-form">
<h2 class="ml15" for="message">TELL A TRUTH</h2>
<div class="wrappy">
<!-- for natural flow, you want to shift #test to above the input, so that input can stack on top of it -->
<h1 id="test" class="ml13"></h1>
<input type="text" id="message" name="message" autocomplete="off" class="ml14">
<!-- <h1 id="test" class="ml13">I love your music!</h1> -->
</div>
</form>
</div>
<div class="butt">
<button id="btn1" onclick="formCheck();">Ready to Send?</button>
<button id="btn2" style="display: none" onclick="myMove(); setTimeout(showButton, 3000); hideSendButton();">Send!</button>
</div>
</div>

how to add button with editable title using jquery?

I have a simple section in which the user can add multiple buttons on click, I want these buttons names to be the editable meaning user can edit and save the button title as they wish.
Here is UI how it looks when use click add button
I want a user to be able to add button title by placing a mouse on enter button name.
When a user places a mouse on enter a button name a simple pop up text area will appear something like this.
$(document).ready(function() {
$('#btn').on('click', function() {
var buttonWithText = $("<div class='clickarea'>Enter button name</div>")
$(".main-container").append(buttonWithText);
})
})
.main-container {
height: 300px;
width: 400px;
background: red;
}
.clickarea {
height: 60px;
width: 50%;
/* margin: 20px; */
background: green;
display: flex;
justify-content: center;
align-items: center;
margin: 80px auto;
}
#btn {
cursor: pointer;
margin: 20px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="main-container">
</div>
<button id="btn">Add button</button>

For a very simple solution, you can use prompt:
$(document).ready(function() {
$('#btn').on('click', function() {
let text = prompt('enter button text:');
var buttonWithText = $("<div class='clickarea'>"+text+"</div>")
$(".main-container").append(buttonWithText);
})
})
.main-container {
height: 300px;
width: 400px;
background: red;
}
.clickarea {
height: 60px;
width: 50%;
/* margin: 20px; */
background: green;
display: flex;
justify-content: center;
align-items: center;
margin: 80px auto;
}
#btn {
cursor: pointer;
margin: 20px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="main-container">
</div>
<button id="btn">Add button</button>

If I understand correctly, you're desired functionality is something like below. You can achieve this by taking advantage of addEventListener and then creating a new button and adding it to the DOM on click:
EDIT:
I've updated my code based on your comment. I believe it now works according to the second scenario you have described. Let me know if this does not seem like the desired functionality.
function init() {
const buttonEl = document.querySelector('#button-el');
const buttonContainer = document.querySelector('#button-container');
const alertButtonText = e => alert(`You clicked: ${e.target.value}`);
const promptForText = e => {
const text = window.prompt('Enter button text');
if (text && text.trim().length) {
e.target.setAttribute('value', text);
e.target.removeEventListener('mouseover', promptForText);
e.target.addEventListener('click', alertButtonText);
}
}
buttonEl.addEventListener('click', e => {
const newButtonEl = document.createElement('input');
newButtonEl.setAttribute('type', 'button');
newButtonEl.addEventListener('mouseover', promptForText);
buttonContainer.appendChild(newButtonEl);
});
}
init();
#button-container>input {
height: 30px;
width: 40%;
background: green;
display: block;
align-items: center;
margin: 20px auto;
}
body {
background: red;
}
#button-el {
cursor: pointer;
margin: 20px;
}
<input id="button-el" type="button" value="Add button" />
<div id="button-container">
</div>

Assign a value to input field

let slider = document.getElementById("slider");
let rightBtn = document.getElementById("rightbutton");
let leftBtn = document.getElementById("leftbutton");
let element = document.getElementById("elementtype").innerHTML;
let celciusBoiling = document.getElementById("celciusboiling").value;
let chlorine = ["Chlorine", 100, 200];
function moveSliderRight() {
if (rightBtn.onclick) {
slider.value++;
}
}
function moveSliderLeft() {
if (leftBtn.onclick) {
slider.value--;
}
}
function main() {
moveSliderRight();
moveSliderLeft();
if (slider.value == parseInt(2)) {
element = chlorine[0];
celciusBoiling = chlorine[1];
}
}
main();
* {
margin: 0;
padding: 0;
box-sizing: border-box;
background-color: peachpuff;
}
header {
width: 90%;
margin: 10px auto 0px;
}
header h1 {
text-align: center;
border: 1px solid black;
padding: 15px 0px;
}
.navbar {
width: 75%;
margin: 50px auto 50px;
padding: 10px 0px;
display: flex;
justify-content: space-around;
border: 1px solid black;
}
.navlinks {
border-right: 1px solid black;
width: 50%;
text-align: center;
display: block;
}
#nav3 {
border: none;
}
#intro {
margin: 0px auto 50px;
width: 40%;
text-align: center;
}
#slider {
-webkit-appearance: none;
background-color: grey;
width: 90%;
display: block;
margin: auto;
}
#slider::-webkit-slider-thumb {
cursor: pointer;
}
#slider::-moz-range-thumb {
cursor: pointer;
}
#valuetag {
text-align: center;
margin-top:25px;
}
h2 {
text-align: center;
font-size: 45px;
text-decoration: underline;
}
#display {
width: 90%;
margin-left: 50px;
margin-bottom: 50px;
font-size: 40px;
}
#display div {
display: inline-block;
width: 45%;
text-align: center;
}
span {
font-size: 15px;
}
.boiling {
margin-left: 6%;
}
.boilingpointslider {
text-align: center;
}
button {
margin: 20px 20px 20px 0px;
width: 75px;
}
<header>
<h1>Periodic Table Gases - Interative Slider</h1>
<nav>
<div class="navbar">
<div class="navlinks">Boiling Point</div>
<div class="navlinks" id="nav3">Melting Point</div>
</div>
</nav>
</header>
<div id="intro">
<p>Interact with the slider buttons to view the displayed properties held by gases, within the periodic table of elements.</p>
</div>
<h2 id="elementtype">Hydrogen</h2>
<div id="display">
<div class="boiling">
<h2>Boiling Point</h2>
<input id="celciusboiling" type="number" value="0"><span>℃</span>
<input id="fahrenboiling" type="number"><span>℉</span>
<input id="kelvinboiling" type="number"><span>K</span>
</div>
<div class="melting">
<h2>Melting Point</h2>
<input id="celciusmelting" type="number"><span>℃</span>
<input id="fahrenmelting" type="number"><span>℉</span>
<input id="kelvinmelting" type="number"><span>K</span>
</div>
</div>
<input type="range" min="0" max="9" value="0" id="slider">
<div class="boilingpointslider">
<button id="leftbutton" onclick="moveSliderLeft()">Left</button>
<button id="rightbutton" onclick="moveSliderRight()">Right</button>
</div>
I am having issues transferring a value to an input field.
Within the snippet linked their is a heading with the value hydrogen and to the bottom left their is a boiling point heading with a input field for celcius.
I'm trying to achieve a scenario whereby you move the slider along using the buttons and at each value the heading changes to a different element and the input value for just the celcius boiling point changes.
I can't get this to work though. The buttons are working to make the slider move left and right, but for whatever reason i cant get the value to appear within the input field or change the heading. I've displayed the code i have already to get the buttons to move the slider and a snippet of what i thought would allow the changes i want to take place when the slider value changes to 2. I cant get it to to work though
Thanks.

You don't show your HTML, but I presume that slider is an input (text or hidden).
The value attribute is a string, even if you assign it a number, so you need to first convert it to a integer if you want to increment or decrement it, like so:
slider.value = parseInt(slider.value)++ // or --
Note that also you are trying to parseInt(2) down in your main(), which makes no sense as 2 is already an integer.

Javascript: Focus is not a function

I'm writing a registration form and am trying to sort out some validation. I got this same problem when my validate button was inside the <form> however to fix this I just moved it out as I guessed the button was causing the form to refresh.
However now after inserting multiple if statement into the "ValidateForm()" function this error message has seemed to come back.
Error: Uncaught TypeError: Forename.focus is not a function
at ValidateForm (Login Form Complex.html?Forename=&Surname=&Username=&Password=&Email=:79)
at HTMLButtonElement.onclick (Login Form Complex.html?Forename=&Surname=&Username=&Password=&Email=:63)**
function ValidateForm() {
var Forename = document.getElementById("Forename").value;
var Surname = document.getElementById("Surname").value;
var Username = document.getElementById("Username").value;
var Password = document.getElementById("Password").value;
var Email = document.getElementById("Email").value;
var Errors = 0
if (Forename == "") {
document.LoginForm.Forename.focus();
Forename.focus();
Errors = Errors + 1
}
if (Surname == "") {
document.LoginForm.Forename.focus();
Surname.focus();
Errors = Errors + 1
}
if (Username == "") {
document.LoginForm.Forename.focus();
Username.focus();
Errors = Errors + 1
}
if (Password == "") {
document.LoginForm.Forename.focus();
Password.focus();
Errors = Errors + 1
}
if (Errors != 0) {
alert("Please fill in the highlighted boxes")
return false;
}
}
body {
margin: 0;
padding: 0;
background: url(LoginBack.jpg);
background-size: cover;
background-position: center;
font-family: century gothic;
}
.loginbox {
width: 420px;
height: 680px;
background: #5CDB95;
color: #05386B;
top: 50%;
left: 50%;
position: absolute;
transform: translate(-50%, -50%);
box-sizing: border-box;
padding: 70px 30px;
border-radius: 30px;
}
.avatar {
width: 150px;
height: 150px;
border-radius: 50%;
position: absolute;
top: -75px;
left: calc(50% - 75px);
}
h1 {
margin: 0px;
padding: 0 0 20px;
text-align: center;
font-size: 40px;
}
.loginbox p {
margin: 0;
padding: 0;
font-weight: bold;
}
.loginbox input {
width: 100%;
margin-bottom: 20px;
}
.loginbox input[type="text"],
input[type="password"],
input[type="email"] {
border: none;
border-bottom: 1px solid #05386B;
background: transparent;
outline: none;
height: 40px;
font-size: 20px;
color: #379683;
}
.loginbox button[type="Submit"] {
border: 2px solid #05386B;
background: #379683;
height: 40px;
width: 362px;
font-size: 20px;
color: ;
border-radius: 20px;
}
.loginbox button[type="submit"]:hover {
cursor: pointer;
background: #8EE4AF;
}
.loginbox a {
text-decoration: none;
font-size: 15px;
line-height: 20px;
color: #379683;
}
.loginbox a:hover {
cursor: pointer;
color: #8EE4AF;
}
.loginbox input[type="text"]:focus,
input[type="password"]:focus,
input[type="email"]:focus {
border: none;
border-bottom: 1px solid #8B0000;
background: transparent;
outline: none;
height: 40px;
font-size: 20px;
color: #8B0000;
}
<div class="loginbox">
<img src="Logo.jpg" class="avatar">
<h1> Create Account </h1>
<form name="LoginForm">
<p>Forename<p><input type="text" name="Forename" id="Forename" placeholder="Enter Forename here">
<p>Surname<p><input type="text" name="Surname" id="Surname" placeholder="Enter Surname here">
<p>Username<p><input type="text" name="Username" id="Username" placeholder="Enter Username here">
<p>Password<p><input type="password" name="Password" id="Password" placeholder="Enter Password here">
<p>Email<p><input type="email" name="Email" id="Email" placeholder="Enter Email here">
<!--
<p>Gender<p><input type="radio" id="Male" name="Gender" value="Male">Male</input>
<input type="radio" id="Female" name="Gender" value="Female">Female</input>
-->
<button onclick="ButtonSubmit()" type="Submit" value="True" name="ButtonSubmit"> Submit </button><br /><br />
Forgot your password? <br />
Already got an account? <br /><br />
</form>
<button onclick="ValidateForm()"> Validate </button>
</div>

Your Forename variable is not holding a reference to a DOM element. It is referencing the .value of that element. The same is true for all of your other DOM variables.
var Forename = document.getElementById("Forename").value;
The value doesn't have a .focus() method. The element does.
In general, it's best not to set variables to properties of DOM elements because, if you determine later that you need a different DOM property, you have to scan the DOM again for a reference you already scanned for. Additionally, setting variables to the DOM elements themselves, and not properties of the elements, will prevent your error, which is very common.
So, change your variables to be set up like this:
var Forename = document.getElementById("Forename");
And then, when you need the value, you can just write:
Forename.value
And, when you want to use the focus() method, just write:
Forename.focus();
You can access whatever aspect of the element you want if you always start from the element itself.

E.g.Forename var have the value of Forename input element then:
var Forename = document.getElementById("Forename"); //DOM element
var fornameValue = Forename.value //value
Forename.focus() //focus function