I need to create 2 arrays in JS from an input value. The first should contain all my inputs values and the second one should contain all my inputs values but for the last one.
I tried this but it doesn't work.
<body>
<input type="text"></input>
<button>click</button>
<script>
var input = document.querySelector("input");
var button = document.querySelector("button");
button.addEventListener("click" , clickHandler , false);
var valori = [];
var comp = [];
function clickHandler()
{
n = input.value;
for (var i =0; i < 10; i++)
{
valori.push(parseInt(n));
comp = valori.pop();
console.log(valori);
console.log(comp);
break;
}
}
</script>
</body>
The ideea is that I want to check if an input value has been entered before. I thought of doing that by creating 2 arrays like I mentioned before and then compare "n" to the "comp" array
if you are just to check element exist or not.. why dont u why indexOf(n)??
no need to create two array and for loop etc etc.. just indexOf will work for you..
check the below code..
<html>
<body>
<input type="text"></input>
<button>click</button>
<script>
var input = document.querySelector("input");
var button = document.querySelector("button");
button.addEventListener("click" , clickHandler , false);
var valori = [];
function clickHandler()
{
if(isNaN(input.value))
{
alert('value is not a Number');
}
else
{
var nbr = parseInt(input.value);
if(valori.indexOf(nbr) < 0)
{
valori.push(nbr);
input.value="";
}
else
{
alert('element already exists.');
}
}
}
</script>
</body>
</html>
U are setting value on comp which is array u need to set value at index .
function clickHandler()
{
var is = true;
var n = parseInt(document.getElementById("inp").value);
if(!isNaN(n))
{
for (var i =0; i < valori.length; i++)
{
if(n === valori[i])
{
console.log("duplicate");
is = false;
break;
}
}
if(is)
valori.push(n);
}
console.log(valori);
}
DEMO
Related
Please I have two arrays
Var subject("goat","man");
Var predicate ("enter", "come");
I want to make a search page that will display the results if the input items matches the two arrays
Please help
var subject = ['goat','man'];
var predicate = ['enter', 'come'];
var i;
function my_func(){
var search_value = document.getElementById('search1').value; //the entered value in the searchbox
for(i = 0; i < subject.length && predicate.length; i++){ //Find the item that you enter in searchbox
if(search_value === subject[i]){ //
document.getElementById('demo').innerHTML = subject[i];
}
if(search_value === predicate[i]){
document.getElementById('demo').innerHTML = predicate[i];
}
}
}
<input type="search" id="search1"> <button onclick = "my_func()">Show</button>
<p id="demo"></p>
I'm doing some exercises and come across where I can't pass the value from the input box to a function inside a script, I don't really know what I have done wrong, I tried different things but didn't really work out. How can I make it work? I want to able to enter a number then press a button so that it prints pyramid according to given number, here is my code :
window.onload = function() {
let aantalLijnen = parseInt(document.getElementById('number').value);
document.getElementById("button").onclick = stars();
function stars() {
for (var i = 1; i <= aantalLijnen; i++) {
var row = '';
for (var j = 1; j <= i; j++) {
row += '*';
}
console.log(row);
}
}
};
<p>Give a number betweeen 2 and 10
<input type="number" id='number'>
<button id="button">Click</button></p>
You're calling stars() and assigning the result to the onclick handler.
You need to pass the function itself...
document.getElementById("button").onclick = stars;
Or just create an anonymous function directly...
document.getElementById("button").onclick = function() {
...
}
As pointed out by #j08691, you are setting the value of aantalLijnen on the page load.
Instead you want to get the value at the time the function runs, so you need to move it into the function itself...
window.onload = function() {
document.getElementById("button").onclick = function () {
let aantalLijnen = parseInt(document.getElementById('number').value);
for (var i = 1; i <= aantalLijnen; i++) {
var row = '';
for (var j = 1; j <= i; j++) {
row += '*';
}
console.log(row);
}
}
};
<p>Give a number betweeen 2 and 10
<input type="number" id='number'>
<button id="button">Click</button></p>
you have to get the value from input every time you click on the button
window.onload = function () {
const numberElem = document.getElementById('number');
document.getElementById("button").addEventListener('click', stars);
function stars() {
let aantalLijnen = parseInt(numberElem.value);
for (var i = 1; i <= aantalLijnen; i++) {
var row = '';
for (var j = 1; j <= i; j++) {
row += '*';
}
console.log(row);
}
}
};
Besides what already said by others
Don't use onclick handlers. Stick to cumulative listeners with addEventListener
You could use String.prototype.repeat();
Defer your script or place it right before the closing </body> tag
Learn the difference between let and const
function stars() {
const num = parseInt(document.getElementById('number').value, 10);
if (num < 2 || num > 10) return console.log("Use from 2 to 10 inclusive");
const row = '*'.repeat(num);
console.log(row)
}
document.getElementById("button").addEventListener('click', stars);
Give a number betweeen 2 and 10
<input type="number" id='number'>
<button id="button">Click</button>
I want to have a webpage with one input box and two button. first button for adding input box value to my array and the second to sum all array values. but it return 0 :(
<input type="text" placeholder="Enter number" id="input">
<button id="add">Add to Array</button>
<button id="sum">Sum All</button>
<p id="text"></p>
<script>
var myArr = []; //contain numbers that i've inputed
var input = document.getElementById('input');
var addBtn = document.getElementById('add');
var sumBtn = document.getElementById('sum');
addBtn.onclick = function () {
myArr.push(input.value);
input.value = "";
}
function sumAll() {
var i , sum = 0;
for ( i in myArr.length ) {
sum += i;
}
return sum;
}
sumBtn.onclick = function(){
var paragraph = document.getElementById('text');
var a = sumAll();
paragraph.innerHTML = a;
}
</script>
You can use the for-of syntax to loop thru your array.
function sumAll() {
var i , sum = 0;
for ( i of myArr ) {
sum += Number(i);
}
return sum;
}
You need to run your for loop properly:
When you say for ( i in myArr.length ) {the value of i comes out as undefined so the summation never happens. You should use debugging to figure out such issues.
function sumAll() {
var i, sum = 0;
for (i = 0; i < myArr.length;i++) {
sum += +myArr[i];
}
return sum;
}
Notice +myArr[i];that uses unary operator +. This can attempt to convert the string in the input field to number(both int and floats).
https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Expressions_and_Operators#Arithmetic_operators
This should be way to go..
1.You have to use parseInt to treat values as ints
2.Loop correctly over array
<script>
var myArr = []; //contain numbers that i've inputed
var input = document.getElementById('input');
var addBtn = document.getElementById('add');
var sumBtn = document.getElementById('sum');
addBtn.onclick = function () {
myArr.push(input.value);
input.value = "";
}
function sumAll() {
var i , sum = 0;
for ( i in myArr ) {
sum += parseInt(myArr[i]);
}
return sum;
}
sumBtn.onclick = function(){
var paragraph = document.getElementById('text');
var a = sumAll();
paragraph.innerHTML = a;
}
</script>
I have a program that is supposed to take two numbers entered by the user and send them to a function. This function will be used to determine all the prime numbers between those two numbers. However, I just can't seem to figure out how to find all the primes. I created an array that should hold all numbers between the two user submitted ones. But I don't know how to iterate through it and place all the prime numbers found into a new array. I know it's basic stuff, but for some reason I just can't figure it out.
Here's the code for my function so far.
function displayPrimeNumbers(p1, p2) {
var numbers = [];
var primes = [];
for(i = p2; i == p1; i++){
numbers.push(i);
for(i = 0; i < numbers.length; ++i){
if () {
}
}
}
}
<html>
<head>
<script = "text/javascript>
function prime(num1,num2)
{
var s="";
var count=0;
for(i=parseInt(num1);i<num2;i++)
{
for(j=2;j<i;j++)
{
if(i%j==0)
{
count ++ ;
}
}
if(count == 0)
{
s=s+"\n"+i;
}
count = 0;
}
document.getElementById('textarea1').value = s;
}
</script>
</head>
<body>
<input type = "text" id = "num1">
<input type = "text" id = "num2">
<input type = "button" value = "Click here" onclick = "prime(document.getElementById('num1').value,document.getElementById('num2').value)"><br>
<textarea id = "textarea1" rows="10" cols = "20">answer</textarea>
</body>
</html>
I have a text array. I want to display the first entry on page load. And then replace the text with the next entry when I click a button. If I keep clicking the button I want the text to continuously be replaced by waht is next in the array, and when it gets to the end start back at the first entry. Can someone please show me an example code for that. I am new to this.
Here's what I have
$(document).ready(function(){
var arr = new Array("One","Two","Three");
var len=arr.length;
$('#next').click(function(){
for(var i=0; i<len; i++) {
$('#quote').html(arr[i]);
}
});
});
Something like the following should do the trick:
<script type="text/javascript">
var nextWord = (function() {
var wordArray = ['fe','fi','fo','fum'];
var count = -1;
return function() {
return wordArray[++count % wordArray.length];
}
}());
</script>
<p id="foo"> </p>
<button onclick="
document.getElementById('foo').innerHTML = nextWord();
">Update</button>
Edit
Radomised version:
var nextWord = (function() {
var wordArray = ['fe','fi','fo','fum'];
var copy;
return function() {
if (!copy || !copy.length) copy = wordArray.slice();
return copy.splice(Math.random() * copy.length | 0, 1);
}
}());
The following should do it http://jsfiddle.net/mendesjuan/9jERn/1
$(document).ready(function(){
var arr = ["One","Two","Three"];
var index = 0;
$('#next').click(function(){
$('#quote').html(arr[index]);
index = (index + 1) % arr.length ;
});
});
Your code was writing all three values each time you clicked it (but only displaying that last value)
I think something like this would work
The javascript would look like:
// assuming maxTextArrayIndex & textArray are defined & populated
var textDisplayIndex = -1;
document.getElementById('textDisplay').innerHTML = textArray[textDisplayIndex];
function nextElement()
{
textDisplayIndex += 1;
if (textDisplayIndex > maxTextArrayIndex)
{
textDisplayIndex = 0;
}
document.getElementById('textDisplay').innerHTML = textArray[textDisplayIndex];
}
The html would look like:
<body onLoad=nextElement()>
...
<elementToDisplayText id=textDisplay></elementToDisplayText>
<button onClick=nextElement()>Next</button>