Develop Reference

How to change dynamically the index of JavaScript file according to eventlistener

I am using the following code to get the answers and questions of json file:
$(document).ready(function () {
$.getJSON("data.json", function (json) {
var anserFor1st = json.questions[0].answers;
var anserFor2nd = json.questions[1].answers; //If it's more than two use a loop
document.getElementById("content").innerHTML = JSON.stringify(anserFor1st) + "<br/>" + JSON.stringify(anserFor2nd);
var aString = "";
Object.keys(anserFor1st).forEach(function (k) {
aString += anserFor1st[k] + "<br/>";
});
Object.keys(anserFor2nd).forEach(function (k) {
aString += anserFor2nd[k] + "<br/>";
});
document.getElementById("content").innerHTML = aString;
});
});
Instead I want to change dynamically the index of the answers&question, aka write the following:
var anser = json.questions[i].answers;
I have to change the index according to event-listener to clicking next and forward buttons in the html file.
How do I change the index dynamically?

I think you mean you want this:
$(document).ready(function () {
$.getJSON("data.json", function (json) {
var answers = [];
var aString = "";
for (var i = 0; i < json.questions.length; i++)
{
answers[i] = json.questions[i].answers;
document.getElementById("content").innerHTML += JSON.stringify(answers[i]) + "<br/>";
for (var j = 0; j < answers[i].length; j++)
{
aString += answers[i][j] + "<br/>";
}
}
document.getElementById("content").innerHTML = aString;
});
});
This code does exactly what yours did, but there are some things in there that make no sense (such as first loading the json.questions[i].answers into the content element, only to then replace it a few lines later with the contents of aString.) You also stringify the JSON before placing it into the DOM, but I'd have expected you to do the opposite (parsing it, since you already just retrieved it as JSON, so stringifying it again shouldn't do anything).
Basically, I'm not entirely sure what you mean by your question, so if I misunderstood please clarify your question.
EDIT: if your problem is just remembering which question you're on, make a variable to hold the number of the current question (e.g. var currentQuestion = 1;), and then just change that based on what button is clicked.
For example:
$("#buttonPrevious").on("click", function (e)
{
currentQuestion--;
});
$("#buttonNext").on("click", function (e)
{
currentQuestion++;
});
Of course you can check for minimum/maximum question numbers (for example, your max number of questions can be equal to the last value of i in the loop above).

How to stop innerHtml repeating itself over and over again in a table?

I have made an array with objects that get there info from three different user variables, however on one of these there are many sub variables that i don't want it to repeat itself every time the user presses the select button(which updates the table) instead i want it to just add onto (or take away) from the sections that it already has in the table. thanks(if you need the variable code let me know) I have been trying to solve thi for a while now! please help!!
//creating array
var gProducts = new Array();
var gTotalCost = 0;
// Adding Products to array gProducts
function addProduct
{
var product = new Object();
product.name = name;
product.cost = cost;
gProducts.push(product);
gTotalCost += parseInt(cost)
}
//Getting products from array, use of for in loop setting new table rows in blank var for each array item
function renderProducts()
{
var HTMLadd = ""
for (var i in gProducts)
{
if( gProducts[i].cost > 0){
HTMLadd = HTMLadd +
"<tr>"+
"<td class='tableSettings00' id=tableRow2 >" + gProducts[i].name +
"</td>"+
"<td class='tableSettings'>€<span id=tableRow2part2>" + gProducts[i].cost +
"</span></td>"+
"</tr>";
}
else
{
}
}
document.getElementById('tableRow').innerHTML = HTMLadd;
}

You're using a for in loop, when you probably wanted just a for loop.
Change this line to
for (var i in gProducts)
to
for (var i = 0; i < gProducts.length; i++)
With a for/in loop, the variable i will be an object, and not an integer.

Save and print list with array

I need help print and save element in an array in javascript. I know that I have to create an array, and then use a for-loop to save and print it, but i don't know how. What i want to do i so make a simple currency converter, use a for-loop with an array to save the converted input and display it. Here is my code:
JAVASCRIPT
var input = document.querySelector("#input");
var convert = document.querySelector("#convert");
var dollar = 0.51;
var euro = 0.11;
omvandla.onclick = function (){
if(isNaN(input.value)){
alert ("Use numbers");
}
else{
console.log(("Dollar:" + input.value*dollar) + ("Euro:" + input.value*euro));
}
};
HTML
<p>
<form>
<label>Kronor: <input type="text" id="kronor"/></label>
<br><input type="submit" id="convert" value="Omvandla"/>
</from>
</p>
How can I append the converted value after the submit button?

If you want to display one Conversion Result after another, you could do this like this:
var input = document.querySelector("#kronor");
var convert = document.querySelector("#convert");
var dollar = 0.51;
var euro = 0.11;
var conversionArray = [];
convert.onclick = function (){
if(isNaN(input.value)){
alert ("Use numbers");
}
else{
var dollarResult = input.value*dollar;
var euroResult = input.value*euro;
var newArrayEl = {
dollar: dollarResult,
euro: euroResult
};
conversionArray.push(newArrayEl);
console.log(conversionArray);
document.getElementById("convertedValue").innerHTML = "Dollar: " + dollarResult + " Euro: " + euroResult + "<br>" + document.getElementById("convertedValue").innerHTML;
}
};
Then you can access single values of the conversion by e.g. conversionArray[indexOfElement].dollar
This way you don't need an array to store the values. If you really need thos wvalues again, let me know, and im showing you how to store the array.
Here is a Fiddle, that shows how it works.

In javascript the way you add elements to an array is the push function
var myArray = [];
myArray.push(15);
Then to loop through the elements you can do something like this
for(var elem in myArray){
//Do something with elem
}
From your problem description it is hard to figure out what you are trying to do with your code. Hopefully this will help with array manipulation

You can add an element to the end of an array by using the array.push() function. I your example you would do something like:
array = [];
...
omvandla.onclick = function (){
if(isNaN(input.value)){
alert ("Use numbers");
}
else{
console.log(...);
array.push(input.value);
}
};
For more information about JavaScript arrays see here.

Log input into array, print only new input

Okay I have a a couple of functions. I don't think most of them are relevant. What I want to do is create an html list when you click a button, and store the value in an array. However I want to be able to update this list without outputting the entire array again. I have it set up to accept the input and I can get it to loop and print the array but it will print the entire array and I only want one. This seems like a common thing but my Google-fu returned nothing.
So I have a list variable that connects to an input, logs it into an array, and another function to clear it and print out the values.
Code snippet:
var listItemInput= document.getElementByID("listItem");
var listItem= [];
function insertListItem(){
listItem.push(listItemInput.value);
clearAndShow();
}
function clearAndShow(){
listItemInput.value= "";
}
function printList{
for (var i = 0; i < listItem.length; i++){
document.getElementById("list").innerHTML += '<li>' + listItem[i] + '</li>';
}
When the printList funciton is called by pressing the button it prints the entire array over however I would like a button that simply prints the newest item. How could I do that?
For clarification, I need to print out the list to html and store the values in an array, the values will later be referenced in an if else argument to combine and print them with new variables.
EDIT:
I plugged in the var = lastIndex and changed it as well as made two more variables for my list. This seems to make it work. Thank you.

You could keep track of the last index printed.
var listItemInput= document.getElementByID("listItem");
var listItem = [];
var lastIndex = 0; //Keep track of the last index shown.
function insertListItem() {
listItem.push(listItemInput.value);
clearAndShow();
}
function clearAndShow() {
listItemInput.value = "";
}
function printList() {
for (; lastIndex < listItem.length; lastIndex++) {
document.getElementById("list").innerHTML += '<li>' + listItem[lastIndex] + '</li>';
}
}
This approach assumes you won't be removing items from listItem array, which you didn't express is something that would be done.

If you only want one element, why do you need to iterate?
function printList() {
document.getElementById('list').innerHTML = '<li>' + listItem[listItem.length-1] + '</li>';
}

function to change argument to another sign

I dynamically create this list element and information a user has typed in shows up in it when a button is clicked 'info' is text and shuld show as it is but 'grade' is a number that i want to convert to another sign with the function changeNumber() but I am new to javascript and cant figure out how to make this function, can anyone give a suggestion or point me in the right direction?
var list = $("#filmlista");
var list_array = new Array();
function updateFilmList()
{
document.getElementById("name").value = '';
document.getElementById("star").value = 0;
var listan = list_array[0][0];
var grade = list_array[0][1];
var element = '<li class="lista">' + list + '<span class="grade">'+ changeNumber(grade) +'</span></li>';
list.append(element);
}
should I use innerHTML? not shure I understand how it works? and how do I use the replace method if I have to replace many different numbers to the amount of signs the number is?
for example if the number is 5 it should show up as: *****, if number is 3 show up as: *** and so on

Here's some code that should do the trick:
Add this function into your script.
function changeNumber(number) {
var finalProduct = "";
for (var i = 0; i < number; i++) {
finalProduct += "*";
}
return finalProduct;
}
Replace the updateFilmsList with this code.
document.getElementById("name").value = '';
document.getElementById("star").value = 0;
var listan = list_array[0][0];
var grade = changeNumber(list_array[0][1]);
var element = '<li class="lista">' + list + '<span class="grade">'+ grade +'</span></li>';
list.append(element);

It looks like you're trying to do something like PHP's str_repeat. In that case, take a look at str_repeat from PHPJS

There are options other than a loop:
function charString(n, c) {
n = n? ++n : 0;
return new Array(n).join(c);
}
charString(3, '*'); // ***
You can use innerHTML to set the text content of an element provided none of the text might be mistaken for markup. Otherwise, set the textContent (W3C compliant) or innerText (IE proprietary but widely implemented) property as appropriate.