Develop Reference

How do i change the backgroundcolor of a form element when clicked?

I've been trying to figure out how I can change the background color of a form element when it is clicked on.
Heres the code:
<form id="form">
<input type="text" placeholder="text"/>
<input type="password" placeholder="more text" />
</form>
<script>
</script>
I'm trying to make it so the form element where it says "text" turns green when clicked, and the form element where it says "more text" turns red when clicked.
I've tried this, which didn't work:
<script>
let form = document.queryselector('input type="text"');
form.addEventListener('click', () => {
form.style.backgroundColor = 'green'
});
</script>
I'm very new to coding, so any help is very much appreciated! Thanks!

you should write ('input[type="text"]');
<script>
let form = document.querySelector('input[type="text"]');
form.addEventListener("click", () => {
form.style.backgroundColor = "green";
});
</script>

If you just want the input background to change color while it's focused. You can achieve this by using CSS selectors. No need for JS
input[type=text]:focus {
background-color: red;
}
Or if you want the form background to change
form:focus-within {
background-color:red;
}

The issue is with this line:
let form = document.queryselector('input type="text"');
First of all - the querySelector() method is camel cased - note the capital S. Secondly, your selector is not quite correct - you're looking for: input[type="text"]:
let form = document.querySelector('input[type="text"]');
form.addEventListener('click', () => {
form.style.backgroundColor = 'green'
});
<form id="form">
<input type="text" placeholder="text"/>
<input type="password" placeholder="more text" />
</form>
Notice though that this doesn't change the background colour back once you focus out - you might be better off adding event listeners for the focusout, focusin and maybe blur events - but better still, you can use CSS:
form input[type="text"]:focus {
background-color: green;
}

I would recommend add and Id or a css class into your input tag then you can use querySelector --> https://www.w3schools.com/jsref/met_document_queryselector.asp

Javascript Function that shows and hides Div based on Checkboxes Dynamically

So I'm building a form in HTML that makes use of a lot of checkboxes and hidden Divs. Right now I'm using
function HideDiv1() {
var checkBox = document.getElementById("Check1");
var div = document.getElementById("Div1");
if (checkBox.checked == true) {
div.style.display = "block";
} else {
div.style.display = "none";
}
}
<input type="checkbox" id="Check1">CheckBox to show Div1
<div id="Div1" style="display: none;">I should be hidden, assuming the author didn't mess up!</div>
To hide each div based on the appropriate checkbox. But this means that I am copying and rewriting this function every time and the section where I like to keep my functions is getting quite large. I was wondering if there was an easier way to do this such that I would only need one function and I could dynamically show and hide Divs without needing to copy and rewrite this function every time.
(If there is some easy JQuery solution to this: please keep in mind that I have no clue how to use JQuery)
This may be a duplicate, I saw the answer once before in the past but I have no idea how to find it again :(

You can use data attributes to identify which div to show when the checkbox is changed.
You can do this by listening for the change event on each checkbox and toggling the corresponding div with jQuery.toggle:
$('input[type=checkbox]').change(function(){
$('div[data-id='+$(this).data('target')+']').toggle()
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input type="checkbox" data-target="1">CheckBox to show Div1
<div style="display: none;" data-id="1">Div1</div>
<br/>
<input type="checkbox" data-target="2">CheckBox to show Div2
<div style="display: none;" data-id="2">Div2</div>
Vanilla JS implementation:
document.addEventListener('click', function(e){
if(e.target.matches('input[type=checkbox]')){
let target = document.querySelector('div[data-id="'+e.target.dataset.target+'"]');
target.style.display = target.style.display == "none" ? "block" : "none";
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input type="checkbox" data-target="1">CheckBox to show Div1
<div style="display: none;" data-id="1">Div1</div>
<br/>
<input type="checkbox" data-target="2">CheckBox to show Div2
<div style="display: none;" data-id="2">Div2</div>

You would add an onchange attribute to the checkbox to call a single function called hideDiv and pass it two arguments that are the ids of the checkbox and the div that you are hiding with that checkbox:
onchange="hideDiv("check1","div1")"
...then hideDiv uses the arguments passed to it to toggle the correct div:
function hideDiv(checkId, divId) {
const checkbox = document.getElementById(checkId)
const div = document.getElementById(divId);
if (checkBox.checked == true) {
div.style.display = "block";
} else {
div.style.display = "none";
}
}
Get in the habit of using let for variables that you need to change and const for variables that will not change value instead of var.

How to enable tooltip on disabled button in javascript?

I have a disabled button and i want it to show a tooltip but change it when i enable it again. How do i get this to work i can only use HTML, javascript and css.
This is the button
<div class="right-item"><button class="button ripple" id="print" onclick="printDiv('qr-code')" disabled="disabled">Drucken</div>

Use title
function toggle() {
var button = document.getElementById('button');
if (button.disabled) {
button.disabled = false;
button.setAttribute('title', 'Enabled title');
} else {
button.disabled = true;
button.setAttribute('title', 'Disabled title');
}
}
<button onclick="toggle()">Toggle enable/disable</button>
<button disabled title="Enabled title" id="button">Hover on me</button>

<button disabled title="Hello">Hover on me</button>
This code will show same tool tip for both disabled or enabled button. Have a function which checks the status of button and apply the title value based on it.

You need to add Javascript when you enable button.
In jQuery:
$('#yourElementId').attr('title', 'your new title');
In Javascript:
var myBtn= document.getElementById("yourElementId");
myBtn.setAttribute('title','mytitle');

How to switch between display:none/block of input field using onclick only once?

I would like to change display property of this input (actually of div which contains it) after onclick ("Click here"). This part goes well ... but after clicking again I want it to be hidden again (has display="none" instead of "block" again and so on) and here I have difficulties.
I've tried classList.toggle but ... I' don't want to change classes, I want to change just one property. I know there is also possibility of creating my input field by using Javascript but I presume I'll come to a deadlock again in the same point.
<form role="form">
<p id="mag">Click here!</p>
<div id="switch" class="xxx"style="display:none;" >
<input id="sr"class="offf" autocomplete="off" placeholder="Search" type="text" >
</div>
</form>
document.getElementById("mag").addEventListener("click", function toffi(){
document.getElementById("switch").style.display="block";
console.log(document.getElementById("switch").style.display);
});
http://codepen.io/zeeebra/pen/RgRYxK

Try this:
document.getElementById("mag").addEventListener("click", function toffi(){
var sw = document.getElementById("switch");
if (sw.style.display === "block") {
sw.style.display = "none";
} else {
sw.style.display = "block";
}
console.log(sw.style.display);
});

Changing the state of a button HTML

I have this code in the body of my HTML which acts as a show/hide button and it is styled via CSS. However I only have the option to title the button once i.e 'Read more.." but after the button has been selected I would like it to change to 'Read less'. Here is the code I am using:
<button title="Click to show/hide content" type="button"
onclick="if(document.getElementById('spoiler') .style.display=='none')
{document.getElementById('spoiler')
.style.display=''}else{document.getElementById('spoiler')
.style.display='none'}">Read more...
</button>
Any help would be greatly appreciated, thanks in advance.

Try:
HTML:
<button title="Click to show/hide content" type="button" onclick="func()" id="but">Read more...</button>
<div id="spoiler" style="display:none">TEXT TEXT TEXT</div>
JS:
function func(){
if(document.getElementById('spoiler') .style.display=="none"){
document.getElementById('spoiler').style.display="block";
document.getElementById('but').innerHTML="Read less...";
}
else{
document.getElementById('spoiler').style.display='none';
document.getElementById('but').innerHTML="Read more...";
}
}
DEMO

Firstly, get out of the habit of bundling JavaScript inline as HTML attributes. Look into DOM-scripting centrally from your JS scripts rather than in your HTML.
The essence of what you need to do is to query something each time the button is clicked, and act accordingly. The visibility of the spoiler area, for example.
(Note, you will need to give your button an ID, e.g. mybutton, for this:)
document.querySelector('#mybutton').addEventListener('click', function() {
var
spoiler = document.querySelector('#spoiler'),
showing = spoiler.style.display != 'none';
spoiler.style.display = showing ? 'none' : 'block';
this.textContent = 'Read '+(showing ? 'more' : 'less');
}, false);
So on click, we interrogate the display style of #spoiler. If it's showing, we hide it, and if it's hidden, we show it, updating the button text accordingly.

HTML:
<button id="btn" title="Click to show/hide content" type="button" onclick="readmore()">Read More...</button>
<div id="spoiler" style="display:none">spoiler text</div>
JS:
function readmore(){
var btn = document.getElementById('btn');
var spoiler = document.getElementById('spoiler');
if(spoiler.style.display=='none') {
spoiler.style.display = '';
btn.innerHTML = "Read Less ...";
} else {
spoiler.style.display = 'none';
btn.innerHTML = "Read More ...";
}
}
Here is a DEMO at jsFiddle.