Background: I'm practicing arrays and functions and am having trouble computing the sum of array items. I'm pretty sure there is something wrong with the function I'm writing but I'm not sure what. Using 8 input fields I'm pulling data into a array one item at a time and converted to floating numbers(for now...I'll try to fix that later). I've created a function that will compute the total of this list but it only outputs NaN.
Any suggestions are highly appreciated!
function myfunction() {
list = [];
list[0] = parseFloat(document.getElementById('number1').value);
list[1] = parseFloat(document.getElementById('number2').value);
list[2] = parseFloat(document.getElementById('number3').value);
list[3] = parseFloat(document.getElementById('number4').value);
list[4] = parseFloat(document.getElementById('number5').value);
list[5] = parseFloat(document.getElementById('number6').value);
list[6] = parseFloat(document.getElementById('number7').value);
list[7] = parseFloat(document.getElementById('number8').value);
function total(myvals) {
let total = 0;
for (let i = 0; i <= myvals.length; i++) {
total += myvals[i];
}
return total;
}
document.getElementById('results').innerHTML = total(list);
}
<form>
<input type="text" name="number1" id="number1"><br>
<input type="text" name="number2" id="number2"><br>
<input type="text" name="number3" id="number3"><br>
<input type="text" name="number4" id="number4"><br>
<input type="text" name="number5" id="number5"><br>
<input type="text" name="number6" id="number6"><br>
<input type="text" name="number7" id="number7"><br>
<input type="text" name="number8" id="number8"><br>
<input type="submit" value="Compute Score" onclick="javascript:myfunction()">
</form>
<div id="results"></div>
Here is a simple example using a for loop with querySelectorAll.
Additionally, I cleaned up your code a bit. Run the snippet below:
EDIT: Included some comments to show what's happening.
function myfunction() {
let total = 0;
//get the value for each element being called by querySelectorAll
//add values to total to get a sum
document.querySelectorAll('input').forEach(el => total += +el.value);
//append the new value to the results div
document.querySelector('#results').innerHTML = total;
}
<form>
<input type="text" name="number1" id="number1"><br>
<input type="text" name="number2" id="number2"><br>
<input type="text" name="number3" id="number3"><br>
<input type="text" name="number4" id="number4"><br>
<input type="text" name="number5" id="number5"><br>
<input type="text" name="number6" id="number6"><br>
<input type="text" name="number7" id="number7"><br>
<input type="text" name="number8" id="number8"><br>
</form>
<br/><br/>
<button type="submit" onclick="myfunction()">Compute Score</button>
<br/><br/>
<div id="results"></div>
This is resolved. I was able to fix my source code by removing
"<=" in the for loop and adding "<" in its place. Thanks everyone, I will look over everything else for extra practice!
1 - in HTML forms and their elements use names.
2 - each element of a form can be accessed by name with the form as parent
3 - if several elements have the same name (with the same type of preference) then they form an object collection
PS: I have used here [... myForm.numX] to transform the myForm.numX collection to array, so that it can accept the arry.map () method
this way:
const myForm = document.forms['my-form']
, res = document.getElementById('results')
;
myForm.onsubmit = evt =>
{
evt.preventDefault() // disable submit
let list = [...myForm.numX].map(inp => parseFloat(inp.value))
res.textContent = list.reduce((t,v)=>t+v,0)
// control...
console.clear()
console.log( myForm.numX.length, JSON.stringify(list) )
}
<form name="my-form">
<input type="text" name="numX" placeholder="num 1"><br>
<input type="text" name="numX" placeholder="num 2"><br>
<input type="text" name="numX" placeholder="num 3"><br>
<input type="text" name="numX" placeholder="num 4"><br>
<input type="text" name="numX" placeholder="num 5"><br>
<input type="text" name="numX" placeholder="num 6"><br>
<input type="text" name="numX" placeholder="num 7"><br>
<input type="text" name="numX" placeholder="num 8"><br>
<button type="submit">Compute Score</button>
</form>
<div id="results">..</div>
Related
I am trying to create a JS function to generate 6 random, secure numbers that are inputted in a HTML form. I currently have:
function secureRandomNums(len) {
let array = new Uint8Array(len);
window.crypto.getRandomValues(array);
return array;
}
function getRandomNumbers() {
let elements = form.getElementsByName("number[]");
let nums = secureRandomNums(elements.length);
for (let i = 0; i < nums.length; i++) {
elements[i].value = nums[i]
}
}
In the HTML file I am calling the getRandomNumbers here:
<form action="AddUserNumbers" id="add_numbers_form" method="post" class="forms">
<label for="number1">Number 1:</label><br>
<input type="text" id="number1" name="number[]"><br>
<label for="number2">Number 2:</label><br>
<input type="text" id="number2" name="number[]"><br>
<label for="number3">Number 3:</label><br>
<input type="text" id="number3" name="number[]"><br>
<label for="number4">Number 4:</label><br>
<input type="text" id="number4" name="number[]"><br>
<label for="number5">Number 5:</label><br>
<input type="text" id="number5" name="number[]"><br>
<label for="number6">Number 6:</label><br>
<input type="text" id="number6" name="number[]"><br>
<input type="button" value="Generate numbers!" onclick="getRandomNumbers()"><br>
<input type="submit" id="submit_numbers" value="Submit your numbers" form="add_numbers_form"><br>
</form>
But it is not displaying the values. What am I doing wrong?
I had it working with an implementation of the Math.random() function but this is not as secure as window.crypto.
getElementsByName() is a document level method and not available at element level
Use querySelectorAll() instead to query elements that only exist in the specific form
const form = document.forms[0]
function secureRandomNums(len) {
let array = new Uint8Array(len);
window.crypto.getRandomValues(array);
return array;
}
function getRandomNumbers() {
let elements = form.querySelectorAll('input[name="number[]"]');
let nums = secureRandomNums(elements.length);
for (let i = 0; i < nums.length; i++) {
elements[i].value = nums[i]
}
}
<form>
<input name="number[]" />
<input name="number[]" />
<input name="number[]" />
<input type="button" value="Generate numbers!" onclick="getRandomNumbers()"><br>
</form>
We have a form and need to iterate over some elements to get the final sum to put in a "total" element.
E.g., here is a working starter script. It doesn't NOT iterate over the other ones. It does NOT consider the elements "item*", below, yet but should. Keep reading.
<script>
$( document ).ready(function() {
$('#taxsptotal').keyup(calcgrand);
$('#shiptotal').keyup(calcgrand);
$('#disctotal').keyup(calcgrand);
function calcgrand() {
var grandtot = parseFloat($('#subtotal').val(), 10)
+ parseFloat($("#taxsptotal").val(), 10)
+ parseFloat($("#shiptotal").val(), 10)
- parseFloat($("#disctotal").val(), 10)
$('#ordertotal').val(grandtot);
}
});
</script>
We are adding more to this. Think of having many items in a cart and each one has the same elements for the following where "i" is a number designating an individual item.
<!-- ordertotal = sum of #subtotal, #taxptotal, #shiptotal and #disctotal -->
<input type="text" id="ordertotal" name="ordertotal" value="106.49">
<input type="text" id="taxsptotal" name="taxsptotal" value="6.72">
<input type="text" id="shiptotal" name="shiptotal" value="15.83">
<input type="text" id="disctotal" name="disctotal" value="0.00">
<!-- sum of the cart "itemtotal[i]" -->
<input type="text" id="subtotal" name="subtotal" value="83.94">
<!-- cart items
User can change any itemprice[i] and/or itemquantity[i]
itemtotal[i] = sum(itemquantity[i] * itemprice[i])
-->
<input type="text" name="itemtotal[1]" value="8.97" />
<input type="text" name="itemquantity[1]" value="3" />
<input type="text" name="itemprice[1]" value="2.99" />
<input type="text" name="itemtotal[2]" value="4.59" />
<input type="text" name="itemquantity[2]" value="1" />
<input type="text" name="itemprice[2]" value="4.59" />
<input type="text" name="itemtotal[3]" value="0.99" />
<input type="text" name="itemquantity[3]" value="10" />
<input type="text" name="itemprice[3]" value="9.90" />
(1) User can change any itemprice[i] and/or itemquantity[i], so each needs a keyup. I can do that in php as it iterates over the items.
(2) These elements will have a $('.itemtotal[i]').keyup(calcgrand); (Or function other than calcgrand, if needed) statement, too. That keyup can be added by the php code as it evaluates the items in the cart.
(3) When an element is changed, then the script should automatically (a) calculate the $('[name="itemtotal[i]"]').val() and (b) replace the value for $('[name="itemtotal[i]"]').val().
(4) Then, the script above will use the $('[name="itemtotal[i]"]').val() to (a) replace the #subtotal value and (b) use that value in the equation.
Can someone help me with this? I am stuck on how to iterate over the [i] elements.
p.s. Any corrections/enhancements to the above code is appreciated, too.
Add a custom class to the desired inputs to sum:
HTML:
<input type="text" class="customclass" name=itemtotal[1] value="8.97" />
<input type="text" class="customclass" name=itemquantity[1] value="3" />
<input type="text" class="customclass" name=itemprice[1] value="2.99" />
JS:
var sum = 0;
$.each('.customclass',function(i, item){
sum = sum + Number($(this).val());
})
alert(sum);
if you for example group your inputs by giving them a class, or have each group in a div like so:
<!-- ordertotal = sum of #subtotal, #taxptotal, #shiptotal and #disctotal -->
<input type="text" id="ordertotal" name="ordertotal" value="106.49">
<input type="text" id="taxsptotal" name="taxsptotal" value="6.72">
<input type="text" id="shiptotal" name="shiptotal" value="15.83">
<input type="text" id="disctotal" name="disctotal" value="0.00">
<!-- sum of the cart "itemtotal[i]" -->
<input type="text" id="subtotal" name="subtotal" value="83.94">
<!-- cart items
User can change any itemprice[i] and/or itemquantity[i]
itemtotal[i] = sum(itemquantity[i] * itemprice[i])
-->
<div class="group">
<input type="text" name="itemtotal[1]" value="8.97" />
<input type="text" name="itemquantity[1]" value="3" />
<input type="text" name="itemprice[1]" value="2.99" />
</div>
<div class="group">
<input type="text" name="itemtotal[2]" value="4.59" />
<input type="text" name="itemquantity[2]" value="1" />
<input type="text" name="itemprice[2]" value="4.59" />
</div>
<div class="group">
<input type="text" name="itemtotal[3]" value="0.99" />
<input type="text" name="itemquantity[3]" value="10" />
<input type="text" name="itemprice[3]" value="9.90" />
</div>
Then you could do the following in javascript:
function calcSubTotal() {
$('[name^="itemtotal"]').each(function(i){
var sum = 0;
$('[name^="itemtotal"]').each(function(i){
sum += $(this).val();
});
$('#subtotal').val(sum);
});
}
$('.group').each(function(i) {
var total = $(this).find('[name^="itemtotal"]');
var qnt = $(this).find('[name^="itemquantity"]');
var price = $(this).find('[name^="itemprice"]');
total.keyup(function(e){
price.val(total.val() * qnt.val());
calcSubTotal();
});
qnt.keyup(function(e){
price.val(total.val() * qnt.val());
calcSubTotal();
});
});
$("[name^='itemprice'], [name^='itemquantity']").keyup(function(){
var input_name = $(this).attr('name');
var temp_name_split = input_name.split(/[\[\]]+/);
var temp_total = parseInt($('[name="itemquantity['+temp_name_split[1] +']"]').val()) * parseFloat($('[name="itemprice['+temp_name_split[1] +']"]').val());
$('[name="itemtotal['+temp_name_split[1]+']"]').val(temp_total.toFixed(2));
var total = 0;
$("[name^='itemtotal']").each(function() {
total += parseFloat($(this).val());
});
$('#subtotal').val(total.toFixed(2));
});
Can any one help me with this, I'm trying to use this code on a POS to calculate the change to give a customer and it works for the must part.
The problem I'm having is if I an order costs £9.99 and I enter £10, instead of it calculating the change as £0.01 it calculates it as £ 0.009999999999999787
Here is the code that I'm using.
function sum() {
var og_total = document.getElementById('og_cart_total').value;
var og_tendered = document.getElementById('og_cash_tendered').value;
var og_change = (og_tendered - og_total).toFixed(2);
var og_symbol = '£';
if (!isNaN(og_change)) {
document.getElementById('og_change_given').value = og_symbol + og_change;
}
}
<input type="hidden" id="og_cart_total" value="19.99" onkeyup="sum();" />
<div class="control-group">
<label class="control-label" for="og_cash_tendered">Tendered:</label>
<div class="controls">
<input class="cm-autocomplete-off" type="text" name="payment_info[og_cash_tendered]" value="" id="og_cash_tendered" onkeyup="sum();" />
</div>
</div>
<div class="control-group">
<label class="control-label" for="og_change_given">Change:</label>
<div class="controls">
<input type="text" name="payment_info[og_change_given]" id="og_change_given" value="£-19.99" readonly="readonly" />
</div>
</div>
there is this way but it's not as promising as it should. the best way is to use a library for long numbers if it worth the trouble.
function sum() {
var og_total = document.getElementById('txt1').value;
var og_tendered = document.getElementById('txt2').value;
var og_change = (og_tendered - og_total).toFixed(2);
var og_symbol = "£";
if (!isNaN(og_change)) {
document.getElementById('og_change_text').value = og_symbol + og_change;
}
}
<input type="text" id="txt1" value="9.99" readonly="readonly" onkeyup="sum();" />
<input type="text" id="txt2" onkeyup="sum();" />
<input type="text" readonly="readonly" id="og_change_text" />
Ok, so I am trying to push the value of an HTML form input to a JavaScript array. When I load the page and submit values through the form, it returns empty strings in the array. I don't understand why this is happening. Thank you for your help.
Relevant HTML:
<form>
<div class="form-group">
<label for="name1">Name: </label>
<input type="text" class="form-control b" id="nameone">
<label for="pref1">Preferences: </label>
<input type="text" class="form-control a" id="prefone"> </div>
<div class="form-group">
<label for="name2">Name: </label>
<input type="text" class="form-control c" id="nametwo">
<label for="pref2">Preferences: </label>
<input type="text" class="form-control a" id="preftwo"> </div>
<div class="form-group">
<label for="name3">Name: </label>
<input type="text" class="form-control d" id="namethree">
<label for="pref3">Preferences: </label>
<input type="text" class="form-control a" id="prefthree"> </div>
<div class="form-group">
<label for="name4">Name: </label>
<input type="text" class="form-control e" id="namefour">
<label for="pref4">Preferences: </label>
<input type="text" class="form-control a" id="preffour"> </div>
<!-- ... -->
<button type="submit" class="btn btn-primary" id="sbm">Submit</button>
</form>
Relevant JavaScript:
var table1 = [];
var table2 = [];
var table3 = [];
var table4 = [];
var names = [];
var pref = [];
// ...
function namesdefine() {
names.push(document.getElementById('nameone').value);
names.push(document.getElementById('nametwo').value);
names.push(document.getElementById('namethree').value);
names.push(document.getElementById('namefour').value);
names.push(document.getElementById('namefive').value);
names.push(document.getElementById('namesix').value);
names.push(document.getElementById('nameseven').value);
names.push(document.getElementById('nameeight').value);
names.push(document.getElementById('namenine').value);
names.push(document.getElementById('nameten').value);
names.push(document.getElementById('nameeleven').value);
names.push(document.getElementById('nametwelve').value);
names.push(document.getElementById('namethirteen').value);
names.push(document.getElementById('namefourteen').value);
names.push(document.getElementById('namefifthteen').value);
names.push(document.getElementById('namesixteen').value);
names.push(document.getElementById('nameseventeen').value);
names.push(document.getElementById('nameeighteen').value);
names.push(document.getElementById('namenineteen').value);
names.push(document.getElementById('nametwenty').value);
names.push(document.getElementById('nametwentyone').value);
names.push(document.getElementById('nametwentytwo').value);
names.push(document.getElementById('nametwentythree').value);
names.push(document.getElementById('nametwentyfour').value);
console.log(names);
var testvar = document.getElementById('nameone').value;
console.log(testvar);
console.log("Look here please");
}
document.getElementById('sbm').onclick = namesdefine();seat(document.getElementsByClassName('a').value);check();changeHTML();
console.log(table1);
console.log(table2);
console.log(table3);
console.log(table4);
console.log("second call");
You're calling the namesdefine() function when you assign to .onclick. You should be assigning the function to .onclick, so leave out the () after it.
document.getElementById('sbm').onclick = namesdefine;
Either use:
document.getElementById('sbm').onclick = namesdefine;
Or
document.getElementById('sbm').addEventListener('click', namesdefine);
If you need to call them all, use this:
document.getElementById('sbm').onclick = function () {
namesdefine();
seat(document.getElementsByClassName('a').value);
check();
changeHTML();
}
And it's always a good practice to check for null after getElementById()
Try to get your data in a loop.
You can use getElementByTagName or getElementByClassName.
var elements = document.getElementsByTagName("input")
for (var i = 0; i < elements.length; i++) {
//Create array here arr.push(elements[i].value);
}
You can call that in your click function.
Hope that helps.
I have 5 textbox in html. I want to merge their values. All of them have one name. How can I do it?
<input type="text" name="textbox1">
<input type="text" name="textbox1">
<input type="text" name="textbox1">
<input type="text" name="textbox1">
<input type="text" name="textbox1">
Get the values as an array, and join it
var val = [].map.call( document.getElementsByName('textbox1'), (el) => el.value ).join('');
var values = [].map.call( document.getElementsByName('textbox1'), (el) => el.value ).join('');
console.log(values)
<input type="text" name="textbox1" value="a1-">
<input type="text" name="textbox1" value="a2-">
<input type="text" name="textbox1" value="a3-">
<input type="text" name="textbox1" value="a4-">
<input type="text" name="textbox1" value="a5-">
If you want to select by the name attribute of your inputs, use getElementsByName like this:
var inputs = document.getElementsByName("textbox1");
var inputValues = "";
for(var index=0; index < inputs.length; index++) {
inputValues += inputs[index].value;
}