Develop Reference

How to set minimum Increment ++ and Decrement -- value (can't go bellow 1) + how to decrease or increase button added value

I am working on a web store which offers 2 pre-assigned options (buy two for XX and buy 3 for XY). I also added a normal - 0 + system whith which the customer can select a different number of products.
I wrote a little code which works fine for +- or 2,3 alone, but if i wanna decrease a number added by 2,3 buttons, it doesn't go from 3 to 2 but to 0 or -1.
So, i want to be able to select pre-defined option 2 or 3 but i also want it to be editable by +- buttons.
Any suggestions?
<button class="gumb_shop2" onclick="spremembax()">2 for 10,99 €</button>
<button class="gumb_shop3" onclick="spremembay()">3 for 8,99 €</button>
<button class="plus" onclick="buttonClickUP();">+</button>
<input type="text" id="gumb2" value="0"></input>
<button class="plus" onclick="buttonClicDOWN();">-</button>
<input type="text" id="order" value="ORDER NOW"></input>
<script>
function spremembax() {
document.getElementById("gumb2").value = "2";
}
function spremembay() {
document.getElementById("gumb2").value = "3";
}
var i = 0;
function buttonClickUP() {
i++;
document.getElementById('gumb2').value = i;
if (i <= 0) {
i = 0;
display(i);
}
}
var i = 0;
function buttonClickDOWN() {
i--;
document.getElementById('gumb2').value = i;
if (i <= 0) {
i = 0;
display(i);
}
}
</script>

As I already mention in the comment, you have a typo in buttonClicDOWN .......missing k. You directly increment/decrement the value of the element. Please see the modified functions:
<button class="gumb_shop2" onclick="spremembax()">2 for 10,99 €</button>
<button class="gumb_shop3" onclick="spremembay()">3 for 8,99 €</button>
<button class="plus" onclick="buttonClickUP();">+</button>
<input type="text" id="gumb2" value="1"></input>
<button class="plus" onclick="buttonClickDOWN();">-</button>
<input type="text" id="order" value="ORDER NOW"></input>
<script>
function spremembax() {
document.getElementById("gumb2").value = "2";
}
function spremembay() {
document.getElementById("gumb2").value = "3";
}
function buttonClickUP() {
var el = document.getElementById('gumb2');
el.value = Number(el.value) + 1;
}
function buttonClickDOWN() {
var el = document.getElementById('gumb2');
if(el.value == 1) return false;
el.value = Number(el.value) - 1;
}
</script>

I'd have this added as a comment, but was not able to for missing rep. So an answer:
In simple terms: you are not updating your global variable i when pressing the 2 or 3 button, so when you in/decrease i and assign it to the value property, you do override the old value.
I would recommend to drop the i (global) variable and just to work with the value property, e.g.
function buttonClickDOWN() {
var elm = document.getElementById('gumb2');
if (elm.value > 0)
elm.value--;
else
elm.value = 0;
}
P.S.: as you are using a text type input, you might also want to consider non-numbers the user might have entered.

Why not simply use input type="number"?
<button class="gumb_shop2" onclick="gumb2.value=2">2 for 10,99 €</button>
<button class="gumb_shop3" onclick="gumb2.value=3">3 for 8,99 €</button>
<input type="number" id="gumb2" value="1" step="1" min="1" />
<input type="button" id="order" value="ORDER NOW" />

Here's a simple example that that meets your specs:
<button onclick="setAbs(event)" data-val="2">2 for 10,99 €</button>
<button onclick="setAbs(event)" data-val="3">3 for 8,99 €</button><br/><br/>
<button onclick="down()">-</button>
<input size="2" id="counter" value="0" />
<button onclick="up()">+</button><br/><br/>
<input type="submit" value="Submit" />
<script>
let counter = document.getElementById("counter");
function setAbs(event){
counter.value = event.target.dataset.val;
}
function up(){
counter.value = parseInt(counter.value) + 1;
}
function down(){
if(counter.value > 0){
counter.value = parseInt(counter.value) - 1;
}
}
</script>

this is the answer i was looking for.
Thank you #Mamun for quick response.
<button class="gumb_shop2" onclick="spremembax()">2 for 10,99 €</button>
<button class="gumb_shop3" onclick="spremembay()">3 for 8,99 €</button>
<button class="plus" onclick="buttonClickUP();">+</button>
<input type="text" id="gumb2" value="1"></input>
<button class="plus" onclick="buttonClickDOWN();">-</button>
<input type="text" id="order" value="ORDER NOW"></input>
<script>
function spremembax() {
document.getElementById("gumb2").value = "2";
}
function spremembay() {
document.getElementById("gumb2").value = "3";
}
function buttonClickUP() {
var el = document.getElementById('gumb2');
el.value = Number(el.value) + 1;
}
function buttonClickDOWN() {
var el = document.getElementById('gumb2');
if(el.value == 1) return false;
el.value = Number(el.value) - 1;
}
</script>

live update value if checkbox is checked or not

I am trying to update a textbox based on whether or not a checkbox is checked or not. Thanks to this post I got a text box working fine, but I can't get a checkbox to update the value. What am I missing?
<html>
<head>
<title>sum totals</title>
<script type="text/javascript">
function calculate(t){
var j = document.getElementById("output");
var rege = /^[0-9]*$/;
if ( rege.test(t.tons.value) ) {
var treesSaved = t.tons.value * 17;
j.value = treesSaved;
}
else
alert("Error in input");
}
$('input[name="selectedItems1"]').click(function(){
var j = document.getElementById("output");
if (this.checked) {
j.value=j.value+300
}else{
j.value=j.value-300
}
});
</script>
</head>
<body>
<form>
<input type="text" placeholder="Tons" id="tons" onkeyup="calculate(this.form)"/>
<br />
<input type="checkbox" name="selectedItems1" value="val1" />I have a car
<br/>
<input type="text" id="output" value="Output" />
</form>
</body>
</html>

Place the <script> tag after <form>
Reason:
When the html page loads, it'll be interpreted line by line. When it come to click(), jQuery will try to find the element input[name="selectedItems1"] which won't be loaded into the DOM at that time. So, jQuery won't attach the click() event handle to that checkbox. That's the reason why your code didn't work.

Try this :
<html>
<head>
<title>sum totals</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script><!-- load jquery -->
<script type="text/javascript">
function calculate(){
var j = document.getElementById("output");
var rege = /^[0-9]*$/;
var tons = $('#tons').val();
if ( rege.test(tons) ) {
val = parseInt(tons);
var treesSaved = val * 17;
if($('input[name="selectedItems1"]').is(":checked"))
{
treesSaved = treesSaved +300;
}
else
{
treesSaved = treesSaved -300;
}
if(isNaN(treesSaved))
j.value=0
else
j.value=treesSaved;
}
else
alert("Error in input");
}
$(function(){
$('input[name="selectedItems1"]').change(function(){
calculate();
});
});
</script>
</head>
<body>
<form>
<input type="text" placeholder="Tons" id="tons" onkeyup="calculate()"/>
<br />
<input type="checkbox" name="selectedItems1" value="val1" />I have a car
<br/>
<input type="text" id="output" value="Output" />
</form>
</body>
</html>

how to have a userinput be ".pushed" into an array

I would like the user to be able to add a url into the box submit it and then it will be in the array and be displayed in order. I would like this to be able to happen as many times as they click submit.
this is where I am but it searches my computer for the url rather than the web.
<!DOCTYPE html>
<html>
<head>
<title>images</title>
</head>
<body>
<input type="text" id="user_input" />
<button onClick="add()">ADD</button>
<img id="light" width="10%">
<button onclick="colourChange()">Click Me To Cycle Through The Colours</button>
<script>
var x=1
var user = document.getElementById("user_input");
var colour = ["red.gif", "amber1.gif", "green.gif", "amber1.gif"];
document.getElementById("light").src = colour[0];
function add(){
colour.push(user);
}
function colourChange(){
document.getElementById("light").src = colour[x];
x += 1;
if (x == colour.length ) x = 0
}
</script>
</body>
</html>

If you want this to be reset when user reloads the page, you don't need to use a form.
<input type="text" id="user_input" />
<button onClick=add()>ADD</button>
And your add function
function add(){
var newVal = document.getElementById('user_input').value;
fruits.push(newVal); //assuming your array is named fruits, I can't see in your code where you have defined it.
}

Replace your add function with
var imageInput = document.querySelector("input[name=url]");
function add(evnt){
evnt.preventDefault();
colour.push(imageInput.value);
return false;
}

First you need to declare the array before you try to push it.
var fruits = [];
and then in your add function, get the url element and push to the array you declared previously. It's convenient if you give the element an id.
function add() { fruits.push(document.getElementById('url').value); }
<!DOCTYPE html>
<html>
<head>
<title>images</title>
</head>
<body>
<form id="user">
insert an image URL to add to cycle: <input type="text" id="url" name="url"><br>
<button onclick="add()">ADD</button>
</form>
<img id="light" width="10%">
<button onclick="colourChange()">Click Me To Cycle Through The Colours</button>
<script>
var x = 1;
var colour = ["red.gif", "amber1.gif", "green.gif", "amber1.gif"];
var fruits = [];
document.getElementById("light").src = colour[0];
var url = document.getElementById('url');
function add(){
fruits.push(url.value);
}
function colourChange(){
document.getElementById("light").src = colour[x];
x += 1;
if (x == colour.length ) x = 0
}
</script>
</body>
</html>

Add into from tag onsubmit="return false" and see add() function which is mentioned in below line.
var x=1
var colour = ["red.gif", "amber1.gif", "green.gif", "amber1.gif"];
document.getElementById("light").src = colour[0];
function add(){
var newVal = document.getElementById('url').value;
colour.push(newVal);
document.getElementById('url').value = '';;
}
function colourChange(){
document.getElementById("light").src = colour[x];
x += 1;
if (x == colour.length ) x = 0
}
<!DOCTYPE html>
<html>
<head>
<title>images</title>
</head>
<body>
<form id="user" onsubmit="return false">
insert an image URL to add to cycle: <input type="text" name="url" id="url"><br>
<input type="submit" value="Submit" onclick="add()">
</form>
<img id="light" width="10%">
<button onclick="colourChange()">Click Me To Cycle Through The Colours</button>
</body>
</html>

cloneNode and total the value of all nodes (parent+childs). Javascript

I want to total the values of all input, but in the beginning there's only one input element and you add the clone(s) with a button. Actually I have two issues:
1. How to place the clone node always under the node before it.
2. How to total the values of all nodes.
Here's the code:
function nambahData() {
var a = document.getElementById("harga");
var b = a.cloneNode(false);
document.getElementById("form").appendChild(b);
}
function ditotal() {
var x = document.getElementById("harga").value;
var y = document.getElementById("harga").childNode.value;
document.getElementById("total").value = parseInt(x) + parseInt(y);
}
</script>
<div id="form">
<input id="harga" type=number>
<br>
</div>
<button onclick="nambahData()">add data</button>
<br>
<button onclick="ditotal()">total all</button>
<input id="total" type=number>

Hope this helps you ..
window.nambahData = function() {
var a = document.getElementsByName("harga");
var b = a[0].cloneNode(false);
document.getElementById("form").appendChild(b);
}
window.ditotal = function() {
var totalItems = 0;
for(i=document.getElementsByName("harga").length-1;i>=0;i--)
{
var item = document.getElementsByName("harga")[i];
totalItems += parseFloat(item.value);
}
document.getElementById("total").value = totalItems;
}
.inputStyle{
display:block;
}
<div id="form">
<input name="harga" type="number" class="inputStyle">
</div>
<button onclick="nambahData()">add data</button>
<br>
<button onclick="ditotal()">total all</button>
<input id="total" type=number>

Trying to get the result of javascript function using innerHTML

I have a simple program that takes in an input and then should show that input multiplied up to 100. I am new to this, but have tried to get it to work before posting here. I have the link to the program that I am referring to.
I want the result to be shown, but I cannot figure out why it is not showing.
You can see what I have below. I think I do not have the html and javascript hooked up properly.
Here is my html:
<body>
<input type="number" id="NumToBMultiplied" class="value" placeholder="Enter an integer" />
<input type='submit' id='RunProg' class='button' />
<p> id='result'</p>
</body>
Here is my Javascript:
h = document.getElementByID('NumToBMultiplied');
var result = document.getElementbyID('RunProg').addEventListener('click', function () {
for (i = 0; i < 100; i++)
return i * h;
}
});
document.getElementByID('result').innerHTML = result;
http://jsbin.com/wayejequxu/1/edit?html,js,output
Any help is appreciated!

From how I understand your code, you are wanting to multiply the input 100 times, then output that into a HTML tag. The result in your example is not being added to the result paragraph as it isn't in the loop.
HTML
This is changed only slightly. Notice the onClick="solve()" to the button instead of adding an event listener.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JS Bin</title>
</head>
<body>
<input type="number" id="NumToBMultiplied" class="value" placeholder="Enter an integer"/>
<input type="submit" id="RunProg" onClick="solve()" class="button"/>
<p id="result"> </p>
</body>
</html>
Javascript
I've added a line break after each result of the for loop so the result is easier to read. And the output is cleared before a new solve() is run.
var output = document.getElementById("result");
function solve() {
var input = document.getElementById("NumToBMultiplied").value;
output.innerHTML = "";
for(i=0; i < 100; i++) {
output.innerHTML += i * input + "<br/>";
}
}
Result here: http://jsbin.com/foduyofewi/1/

You need to store your result in variable inside a callback and set innerHTML also in callback:
document.getElementById('RunProg').addEventListener("click", function() {
var result = 1;
var input = +h.value;
for (var i = 1; i < 100; i++) {
result *= i * input;
}
document.getElementById("result").innerHTML = result;
});
DEMO

Pure Javascript version:
function multiply(x) {
var result = document.getElementById('result');
result.innerHTML = x.value * 100;
}
<input type="number" id="NumToBMultiplied" class="value" onchange="multiply(this)" placeholder="Enter an integer"/>
<p id="result"></p>
This is the jQuery version:
$(document).ready(function() {
$('#NumToBMultiplied').on('change',function(){
$('#result').text($(this).val()*100);
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="number" id="NumToBMultiplied" class="value" placeholder="Enter an integer"/>
<p id="result"></p>

Just some modification to your code to remove some of the typos and errors. I'm not sure you can return the result like how you have done it, a more traditional approach is shown below.
Full code
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<input type="number" id="NumToBMultiplied" class="value" placeholder="Enter an integer" />
<input type='submit' id='RunProg' class='button' />
<p id='result'> </p>
</body>
<script>
h = document.getElementById('NumToBMultiplied').value;
document.getElementById('RunProg').addEventListener('click', function () {
for (i = 0; i < 100; i++){
var result = h*i;
}
document.getElementById('result').innerHTML = result;
});
</script>
</html>