parseFloat return 0-2.00 for -2.00

Question

in the JavaScript I am trying to implement for my aspx page, parsefloat("-2.00') is returning a value 0-2.00

Obviously there is something I am missing out, because parsefloat can handle negative numbers, however, here it is showing me this value in debugging and output is coming out to be 0.

Please help me look into what I may be doing wrong.

The code I am using in the javascript

var A=0;
A = document.getElementById('A').value;
A += (parseFloat(A).toFixed(2));
document.getElementById("C").value = roundToTwo(parseFloat(A) + parseFloat(B));

Thanks

I doubt this is it, but in your question you've got mismatching quotes. It should be `parseFloat('-2.00')`. It works fine for me. — dmlittle, Jul 15 '15 at 06:33
I have actually declared and placed this value in a separate variable, and then placed it in parsefloat. I know this generally is supposed to work, but for me it is giving me 0-2.00 — shivangi kulshrestha, Jul 15 '15 at 06:35
can you share the code? there isn't much we can help with unless we know your implementation as the function behaves as it should. — dmlittle, Jul 15 '15 at 06:36
actually, the ToFixed() function along with giving me two decimal places is giving me the 0-2.00 value for a negative 2.00. Am I not supposed to implement it with negative number? — shivangi kulshrestha, Jul 15 '15 at 06:51

David Votrubec · Answer 1 · 2015-07-15T07:14:17.867

2

UPDATE

See documentation for .toFixed() - it returns a string representation of that number.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toFixed

What you need to do is to split adding two numbers and calling toFixed. Like this

 var A=0; //A is of type number
 A = document.getElementById('A').value; //A is of type string
 A += parseFloat(A); //A is of type number again
 A = A.toFixed(2); //A is of type string again

When you call += on two variables, where one is number and the other is string, then both will be cast to string and simply appended.

edited Jul 15 '15 at 07:14

answered Jul 15 '15 at 06:49

David Votrubec

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not quite the problem. try `var a; a=0; a+= -2.00;` it will have a value of `-2` – dmlittle Jul 15 '15 at 06:56
@dmlittle Thanks for feedback, i have updated my answer – David Votrubec Jul 15 '15 at 07:14
`A += parseFloat(A);` is still a string since the current value of `A` is a string. – dmlittle Jul 15 '15 at 07:26

dmlittle · Accepted Answer · 2015-07-15T07:25:51.657

1

The problem is that when you're getting the value of the HTML element with id A, you're getting a String value. Because you're trying to add a float to a string, your flaot will be automatically converted to a string and therefore concatenanted.

Ensuring A is always a float should solve this issue.

A = parseFloat(document.getElementById('A').value);
A += parseFloat(parseFloat(A).toFixed(2));

edited Jul 15 '15 at 07:25

answered Jul 15 '15 at 06:55

dmlittle

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parseFloat return 0-2.00 for -2.00

2 Answers2