How i add two variables [duplicate] - javascript

This question already has answers here:
How to add two strings as if they were numbers? [duplicate]
(20 answers)
Closed 3 years ago.
how to add two variables, I'm doing it like this and they are concatenating
id('total-quotas').addEventListener('keyup', function () {
id('vl_total').value = (id('total-quotas').value + id('valor6').value);
});

They are concatenating because they are strings.
If you expect those two values to be numeric, then cast them via parseInt.
parseInt(id('total-quotas').value, 10) + parseInt(id('valor6').value, 10)

Are these strings? If they are strings they will contact, if they are integers passed as strings you might need to parse as an integer
See https://www.w3schools.com/jsref/jsref_parseint.asp

Related

Why the plus operator with pure numeric value in string always concat them not actually perform operation on it just like other do? [duplicate]

This question already has answers here:
Adding two numbers concatenates them instead of calculating the sum
(24 answers)
Why does JavaScript handle the plus and minus operators between strings and numbers differently?
(7 answers)
Closed 15 days ago.
Why the + operator with pure numeric value in string always concat them not actually perform operations on string numeric also just like other operators ?
Why they are concating them not did the + operation on it just like -.
For example
"10"-1
< 9
but
"10"+"1" is
<"101" but not
<"11"

parseFloat to display with comma [duplicate]

This question already has answers here:
How to format a number with commas as thousands separators?
(50 answers)
Closed 3 years ago.
Is there a way to use the below JavaScript code to use comma's? For example the var num = 1924.00 Is there way to get it to display as 1,924.00?
var num = parseFloat(totalAmount).toFixed(2);
You could use a specific regex like this one in the function below:
function format_currency( value ) {
return value.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}
If you want to use it in conjuction with the .toFixed(), just do like this:
format_currency( 1245.3.toFixed(2) );
Hope it helps.

Why does it show value 5150 and not 155? [duplicate]

This question already has answers here:
How to add two strings as if they were numbers? [duplicate]
(20 answers)
Closed 4 years ago.
So im quite new to javascript and i tried making something simple as entering a value and add 150 to it but it wont show number + 150?
Pictures below
Code
Output
That's because you are concatenating strings. You need to convert the strings to integers by using parseInt(), and then add the numbers.
https://www.w3schools.com/jsref/jsref_parseint.asp
var fullprice = parseInt(price) + 150;
Because you're actually concatenating a string with a number. The input value is a string, so before operating with it, parse it to int with parseInt
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt

Convert array of strings to array of numbers [duplicate]

This question already has answers here:
convert string array to integer array
(4 answers)
Closed 4 years ago.
I have a jQuery array ["3434", "3433"]
And I would like to make it like [3434, 3433]
No need for jQuery. Supposing you're sure they're all numbers (that is, we're not checking for errors), you can map them with Number, which converts them from string to numbers.
["3434", "3433"].map(Number);
Considering that Number returns NaN in case of error, you may then want to filter the result to remove undesired elements.
let nums = ["3434", "3433", "foo"].map(Number).filter(n => !isNaN(n));
console.log(nums);

(Js) number method to add a comma after the first number and remove the 2 number after comma ?? is there any? [duplicate]

This question already has answers here:
How to round to at most 2 decimal places, if necessary
(91 answers)
Closed 8 years ago.
I want to format a number to two decimal places. Say the user enters 8764444 it should be formatted as 8.76. is there some built-in function in javascript to do that?
No, there is no built in method for exactly that, but you can use the substr method to get parts of a string to do the formatting:
var input = "8764444";
input = input.substr(0, 1) + '.' + input.substr(1, 2);
// show result in Stackoverflow snippet
document.write(input);

Categories