This question already has answers here:
Adding two numbers concatenates them instead of calculating the sum
(24 answers)
Closed 6 years ago.
I'm not sure what's wrong.
There are two variables, cena and uhrada. cena = 10 and uhrada = 279.8. I want to add them but I am getting 279.810 instead of 289.8.
Thanks for any help!
function priplatok(vstup1, vstup2) {
var chid = vstup1;
var cena = vstup2;
var uhrada = document.getElementById('uhr').value;
if (document.getElementById(chid).checked) {
var pridatu = uhrada + cena;
alert(pridatu);
}
}
The reason is that the values you take from the HTML input elements are always strings, even when they look like numbers. You have to first convert them, for instance with parseInt(...) or parseFloat():
var pridatu = parseFloat(uhrada) + parseFloat(cena);
A shorter way is to force conversion with a +:
var pridatu = +uhrada + +cena;
Although this is concise, you should probably first check if the input really is numeric. I refer to a popular question "Validate decimal numbers in JavaScript - IsNumeric()".
You get a string from document.getElementById('uhr').value.
If you want to do math, you need to cast the value either with parseInt(string, 10) or with parseFloat(string) to a number, implicit with a unary plus.
Your code:
function priplatok(vstup1, vstup2) {
var chid = vstup1;
var cena = vstup2;
var uhrada = +document.getElementById('uhr').value; // use implicit cast to number
if (document.getElementById(chid).checked) {
var pridatu = uhrada + cena;
alert(pridatu);
}
}
Thats because the values are strings and not numbers.
You have to make them numbers first and then calculate:
var pridatu = parseInt(uhrada) + parseInt(cena);
Related
This question already has answers here:
How to get numeric value from a prompt box? [duplicate]
(6 answers)
Closed 3 years ago.
I am trying to make an average calculator. This is my code for it:
var data = [];
var yesno = confirm("Would you like to add more data?");
while (yesno) {
var newdata = prompt("Enter a piece of data (must be a number)");
data.push(newdata);
var yesno = confirm("Would you like to add more data?");
}
var total = 0;
var i = 0;
if (!yesno) {
while (i < data.length) {
total += data[i];
i++;
}
}
var average = total / data.length;
document.write(average);
It seems to take input well, however something goes wrong when it comes to calculation. It says that the average of 6 and 6 is 33, 2 and 2 is 11, and 12 and 6 is 306. These are obviously wrong. Thank you in advance for your help.
You need to take a number, not a string value from the prompt.
The easiest was is to take an unary plus + for converting a number as string to a number
data.push(+newdata);
// ^
Your first example shows, with '6' plus '6', you get '66', instead of 12. The later divsion converts the value to a number, but you get a wrong result with it.
It is taking the input as string. Convert the input to floats before putting them in the array. I think its performing string additions like 6+6=66 and then 66/2 = 33. Similar is the case of 2 and 2.
I am calculating 2 fields on a form with values but it seems in some cases it's not working. Here's my javascript. I am adding $oneTimeCostField and $recurringTotalCostField to get the value into the $totalRetailAmountField. Here's the result I am getting when I add say 1,555.00 + 566.00 = the value is 567.00 (?). Any idea what I'm doing wrong? In some cases it works correctly when the values are lower. Thanks, just stumped
var $recurringCostField = $('#am_attribute_campaign_addon_monthly_cost_value');
var $recurringTotalCostField = $('#am_attribute_campaign_addon_total_monthly_cost_value');
var $totalRetailAmountField = $('#am_oie_string_total_monthly_cost_value');
var $oneTimeCostField = $('#am_attribute_campaign_addon_one_time_cost_value');
function calcVal() {
var num1 = $oneTimeCostField.val();
var num2 = $recurringTotalCostField.val();
var result = parseFloat(num1) + parseFloat(num2);
if (!isNaN(result)) {
$totalRetailAmountField.val(result.toFixed(2));
}
}
calcVal();
$oneTimeCostField.on("keydown keyup", function() {
calcVal();
});
$recurringTotalCostField.on("keydown keyup", function() {
calcVal();
});
You need to remove the commas before parsing:
var result = parseFloat(num1.replace(/,/g, '')) + parseFloat(num2.replace(/,/g, ''));
similiar question on this link
Remove commas from the string using JavaScript
That is because parseFloat() converts the string "1,555.00" to the number 1.
To convert it to a proper floating point number, it needs to include a single dot only.
console.log(parseFloat("1.555"));
When i am writing 11.00 it is displaying 11.00.00 otherwise its working fine on rest
if(pos == -1)
{
document.getElementById("printCheckAmount").textContent = "$" + checkObj.checkAmount + ".00";
}
else
{
var integer = enterCheckAmount.substring(0,pos);
var decimals = enterCheckAmount.substring(pos+1);
while(decimals.length<2) decimals=decimals+'0';
enterCheckAmount = integer + '.' + decimals;
document.getElementById("printCheckAmount").textContent = "$" + checkObj.checkAmount;
}
JavaScript doesn't have a variable type for decimal numbers. It has only Number. If you want to display an integer as a decimal number with two zeros after the decimal point you can use the method toFixed.
Here is an example:
var myNumber = 11;
var myDecimalNumber = myNumber.toFixed(2);
console.log(myDecimalNumber) // will output 11.00
Thus there is no need to concatenate strings and add ".00" manually to your number.
Beyond this you can use the methods parseInt and parseFloat. Let's say you have a variable of type string with the value "11 pieces". You can get the integer with this line of code:
var myString = "11 pieces";
var myInteger = parseInt(myString, 10);
console.log(myInteger); // will output 11
If you have something similar like this, you are better off with this methods instead of cuting substrings.
I wish you a lot of success in refactoring your code and a warm welcome to the StackOverflow community.
I'm really new to Javascript and trying to create a form where I'm running into some trouble...
When I use + it does not add up to the value, instead it just puts it back to back. Ex: 5+10 (510)
Here's my code if you want to take a look at it. I'd appreciate any help since I can't figure this out on my own.
var service = document.getElementById("service");
var serviceprice = service.options[service.selectedIndex].id;
var tech = document.getElementById("tech");
var techprice = tech.options[tech.selectedIndex].id;
var hours = document.getElementById("hours").value;
// The error happens here
var total = techprice * hours + serviceprice;
I also have an html part which the script gets the data from.
That happens whenever you have a string rather than a number. The + operator performs concatenation for strings. Make sure you parse your strings to numbers using parseFloat or parseInt:
var service = document.getElementById("service");
var serviceprice = parseInt(service.options[service.selectedIndex].id, 10);
var tech = document.getElementById("tech");
var techprice = parseInt(tech.options[tech.selectedIndex].id, 10);
var hours = parseInt(document.getElementById("hours").value, 10);
Note that parseInt takes an argument to specify the base. You almost always want base 10.
Try changing this line:
var total = techprice * hours + serviceprice;
to
var total = techprice * hours + parseFloat(serviceprice);
I suspect 'servicePrice' is a string, and it will then try to concatenate the first value (let's say: 100) with the second value (which is, not a number, but a string, let's say 'test'), the result being '100test'.
Try to convert the string to int first with parseInt or to float with parseFloat
This is not especially elegant, but I find it simple, easy, and useful:
var total = -(-techprice * hours - serviceprice);
or even:
var total = techprice * hours -(-serviceprice);
They both eliminate the ambiguous + operator.
I am adding a users input in to UI as they add numbers and returning the results. The input is currency so I need to carry it out two decimals and not round.
Here is an example of my code:
function ceiling2(number) {
var ceiling2;
return ceiling2 = Math.ceil(number*100)/100;
}
//Totals
function lD23Total (e){
var app = UiApp.getActiveApplication();
var tB1v = parseInt(e.parameter.TextBox1);
var tB9v = parseInt(e.parameter.TextBox9);
var tB17v = parseInt(e.parameter.TextBox17);
var tB25v = parseInt(e.parameter.TextBox25);
var tB33v = parseInt(e.parameter.TextBox33);
var tB41v = parseInt(e.parameter.TextBox41);
var tB49v = parseInt(e.parameter.TextBox49);
var lD23 = app.getElementById("LabelD23").setStyleAttribute('fontWeight','bold');
var lD23T = tB1v + tB9v + tB17v + tB25v + tB33v + tB41v + tB49v;
lD23.setText("$ " + ceiling2(lD23T));
var app = UiApp.getActiveApplication();
app.close();
return app;
}
Currently it returns a rounded number.
I appreciate an suggestions you may offer!
Jon
The function parseInt() will convert the value to an integer, dropping the values after the decimal. Use parseFloat() instead.
I think your function is just fine...
if you remove the parseInt() and replace it either with parseFloat()as suggested by Eric or by Number() it should work...
if not then the problem might come from the way numbers are written:
If you used 26,4567 but you should use 26.4567 with a dot as separator in place of a comma.
Could you try and keep us informed ?
regards,
Serge
Or you can use this before sending to your function:
var newnumber=Number(number.toString().replace(",","."));// convert to string, replace comma with dot and set as number again.
and your function will work in both cases