Java Script add value of variable to object property? - javascript

I'm new here and to JavaScript. I have an assignment that asks "create a new property in the foodInfo object plus the value of the toppings variable, and set the ne property's value to to value of the current element in the toppingBoxes array."
Here is the code I have that is not working, I have tried multiple things but cant get it to print out the toppings on the page:
for (var i = 0; i < toppingBoxes.length; i++) {
if (toppingBoxes[i].checked) {
toppings = toppings + 1;
foodInfo.topping[toppings] = toppingBoxes[i].value;
}
}
Here is the code the assignment gave me to print it, so this code is correct, but the code above is what I need help with:
foodSummary.innerHTML += "<ul>";
for (var i = 1; i < 6; i++) {
if (foodInfo["topping" + i]) {
foodSummary.innerHTML += "<li>" + foodInfo["topping" + i] + "</li>";
}
}
foodSummary.innerHTML += "</ul>";
I know the code stops running when it hits the line "foodInfo.topping[toppings] = toppingBoxes[i].value;" so I know that is wrong. I am having trouble with the instructions I mentioned above...any help to get this working? Thank you in advance!!

Try this:
var toppings = 0;
for (var i = 0; i < toppingBoxes.length; i++) {
if (toppingBoxes[i].checked) {
toppings = toppings + 1;
foodInfo['toppings' + toppings] = toppingBoxes[i].value;
}
}

Related

Updating a number from a for loop

var currentmix = document.getElementById('custommix').value.split(",");
var additionalprice = 0;
for (i = 0; i < currentmix.length; i++) {
if (currentmix[i] != "") {
var mixinpriceid = "mixinprice"+currentmix[i];
additionalprice += parseFloat(document.getElementById(mixinpriceid).value));
}
}
This code is not working :(
I know the expression
parseFloat(document.getElementById(mixinpriceid).value)
is giving me the right number on each iteration of the loop
But it is not affecting the variable "additionalprice" outside the for loop. Any ways to do this???????
There's a additional parentheses in this statement, please check
additionalprice += parseFloat(document.getElementById(mixinpriceid).value));
Sathish is correct, you have an extra parenthesis. This snippet will show the code will work without it.
var currentmix = "12345";
var additionalprice = 0;
for (i = 0; i < currentmix.length; i++) {
if (currentmix[i] != "") {
var mixinpriceid = "mixinprice" + currentmix[i];
additionalprice += parseFloat(document.getElementById(mixinpriceid).value);
console.log(additionalprice);
}
}
console.log("Final Value: " + additionalprice);
<input id="mixinprice1" value="100">mixinprice1</input>
<input id="mixinprice2" value="200">mixinprice2</input>
<input id="mixinprice3" value="300">mixinprice3</input>
<input id="mixinprice4" value="400">mixinprice4</input>
<input id="mixinprice5" value="500">mixinprice5</input>

Using JS loops to send unique vars from HTML buttons to function

Beginner here. I have a loop that creates 26 buttons with unique ID's and values. What I'm struggling with is figuring out the proper way to send the button's ID to a function so that I can store unique vars for each button independently without creating more than one function. I currently have an array with the 26 items I need for my buttons and the following loop:
function makeButtons() {
for (var i = 0; i < 26; i++) {
document.getElementById("whereButtonsGo").innerHTML += "<input type = 'button' value = '" + items[i] + "' id = 'button" + items[i] + "' onclick = doThing(button" + items[i] + ")'>";
}
}
I want the argument in the onclick function to be sent to a function such as:
function doThing(id) {
document.getElementById("'" + id.value + "'").style.color = "pink";
}
But so far I haven't been able to get this to work. Any help would be greatly appreciated!
Maybe this is what you are looking for:
makeButtons();
function makeButtons() {
for (var i = 0; i < 26; i++) {
document.getElementById("whereButtonsGo").innerHTML += "<input type = 'button' value = '" + i + "' onclick = doThing(this)>";
}
}
function doThing(currentButton) {
currentButton.style.color = "pink";
}
<div id="whereButtonsGo"/>
Try to keep the IDs as simple as possible
I recommend against using innerHTML for creating elements that you actually want to do something. Even if it works, your code will be amazingly unclear. Instead, write code that demonstrates that you're actually creating and adding elements:
var items = [1,2,3,4,5,6];
function makeButtons() {
var container = document.getElementById("whereButtonsGo");
for (var i = 0; i < items.length; i++) {
var button = document.createElement("button");
button.type = 'button';
button.value = items[i];
button.innerText = items[i];
button.id = 'button'+items[i];
button.onclick = doThing;
container.append(button)
}
}
function doThing() {
console.log('click of ' + this.id);
}
makeButtons();
Note that you don't need to pass the id in the function call for the event - the button that was clicked will be available as this.
Here is a fiddle.

JS for loop not working

I have a for loop which looks like this:
for (var i = 0; i < list.length; i++) {
It is looping through Firebase data in the database and returning all the data in the database.
However, I want it to only go up to the first 10 database items. So I changed the loop to:
for (var i = 0; i < 9; i++) {
But this fails to display any results when the there are less than 10 pieces of data in the database. However, if I set the number to however many objects I have in the database, for example 10 because I have 10 objects, it displays them all. But any less than this number and I just get a blank webpage.
Here is the webpage when I have 10 objects in my Firebase database:
And here it is when I remove one of those objects:
I have no idea why this is happening - The logic is correct - if i is less than 9 then display the data - But instead it only displays it when it equals 9.
Here is the full JS:
function refreshUI(list) {
var lis = '';
var lis2 = '';
var lis3 = '';
var lis4 = '';
for (var i = 0; i <= 9; i++) {
lis += '<li data-key="' + list[i].key + '" onclick="addText(event)">' + list[i].book + '</li>';
lis2 += genLinks(list[i].key, list[i].book)
};
for (var i = 10; i < list.length; i++) {
lis3 += '<li data-key="' + list[i].key + '" onclick="addText(event)">' + list[i].book + '</li>';
lis4 += genLinks(list[i].key, list[i].book)
};
document.getElementById('bookList').innerHTML = lis;
document.getElementById('bookList2').innerHTML = lis2;
document.getElementById('bookList3').innerHTML = lis3;
document.getElementById('bookList4').innerHTML = lis4;
};
function genLinks(key, bkName) {
var links = '';
links += '<img src="images/bin.png" style="width: 24px; height: 24px; transform: translateY(-7px); opacity: .4;"></img> ';
return links;
};
function del(key, bkName) {
var response = confirm("Are certain about removing \"" + bkName + "\" from the list?");
if (response == true) {
// build the FB endpoint to the item in movies collection
var deleteBookRef = buildEndPoint(key);
deleteBookRef.remove();
}
}
function buildEndPoint (key) {
return new Firebase('https://project04-167712.firebaseio.com/books/' + key);
}
// this will get fired on inital load as well as when ever there is a change in the data
bookList.on("value", function(snapshot) {
var data = snapshot.val();
var list = [];
for (var key in data) {
if (data.hasOwnProperty(key)) {
book = data[key].book ? data[key].book : '';
if (book.trim().length > 0) {
list.push({
book: book,
key: key
})
}
}
}
// refresh the UI
refreshUI(list);
});
If anybody has any help I'd greatly appreciate it!
When the list size is shorter than 10, you will get an error in the loop because you will eventually address a property (like key) that does not exist on list[i] (since it is undefined). If you would check the console, you would notice that this error is reported.
To fix this, change the condition of the first for loop like this:
for (var i = 0; i < Math.min(10, list.length); i++) {
This way, the loop will never iterate to an entry that does not exist. It will stop after 9 or after list.length-1 whichever comes first.
Alternatively, you can just put the two conditions with an && operator:
for (var i = 0; i < 10 && i < list.length; i++) {

Add certain values from JSON object to javascript array

Update: I've tried the suggestions in the comments and it's still not working. I really have no idea why. I've consolidated it to a single loop and fixed the syntax errors noted. Here's the code as it looks now:
$(function() {
$("#json-one").change(function() {
var $dropdown = $(this);
$.getJSON("washroutines.json", function(data) {
var vals = [];
var $jsontwo = $("#json-two");
$jsontwo.empty();
for (var i = 0; i < data.length; i++){
if (data[i].make === $dropdown.val()) {
$jsontwo.append("<option value=\"" + data[i].model + "\">" + data[i].model + "</option>");
}
}
});
});
});
Any additional help would be much appreciated!
Original question:
I'm trying to create dependent drop down menus using a json object, and I'm having trouble getting the second menu to populate based on the first. When the first menu changes, the second goes to a bunch of "undefined"s.
$.getJSON("washroutines.json", function(data) {
var vals = [];
for (i = 0; i < data.length; i++){
if (data.make = $dropdown.val()) {
vals.push(data.model);
}
}
var $jsontwo = $("#json-two");
$jsontwo.empty();
for (i = 0; i < vals.length; i++){
$jsontwo.append("<option value\"" + vals[i] + "\">" + vals[i] + "</option>");
}
Please use small words when explaining things to me, I'm new at this!
contents of the JSON:
[{"make":"Maytag","model":"Bravos","prewashCycle":"Whitest Whites"},
{"make":"Maytag","model":"Awesome","prewashCycle":"Awesome Whitest Whites"},
{"make":"Whirlpool","model":"Cabrio","prewashCycle":"Extra Heavy"},
{"make":"Kenmore","model":"Elite","prewashCycle":"Awesome"}]
Try changing your for loop for this
for (var i = 0; i < data.length; i++){
if (data[i].make === $dropdown.val()) {
vals.push(data[i].model);
}
}

sending infinity number of checkbox values to text

I have a table with n number of rows with checkboxes and a what i want to do is if i select a checkbox the value should go to the text area, so i stored all elements in an array first, but it isnt happening, as you can see i added alerts as well to check it out. please help.
window.onload = function () {
var oRows = document.getElementById('rnatable').getElementsByTagName('tr');
var iRowCount = oRows.length;
alert('Your table has ' + iRowCount + ' rows.');
var i = 0;
cb = new Array(iRowCount);
while (i <= iRowCount) {
var id = 'check'+ i;
cb[i] = document.getElementById(id);
i++;
}
//alert('Your table has ' + cb[i].value + ' rows.');
for(var a=0; a < iRowCount; a++) {
var fasta = document.getElementById('fasta');
if(cb[a].checked) {
fasta.value = cb.value + ",";
};
};
}
Are you seeing an error in the console? I suspect that when while (i <= iRowCount) runs when i === iRowCount that document.getElementById(id) isn't yielding a result, and that then when you use that value, bad things happen.
Also, each lap through the fasta loop overwrites the previous value. You probably want something like fasta.value += cb.value + ","; instead.

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