How to get a number from HTML form and pass it to JavaScript?

Question

I am trying to calculate Body Mass Index by receiving Weight and Height from HTML form and passing it to JavaScript code by .getElementById();. But, as far as I understand, type of data received from form is "string" and I need to receive a "number". How can I solve this problem?

`parseInt()` and `parseFloat()` should help you – Sirko Dec 22 '15 at 12:56 — Sirko, Dec 22 '15 at 12:56

score 1 · Accepted Answer · answered Dec 22 '15 at 12:58

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Use parseInt().

var a = "10";
var b = parseInt(a);

See : http://www.w3schools.com/jsref/jsref_parseint.asp

answered Dec 22 '15 at 12:58

Léo Martin

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score 0 · Answer 2 · answered Dec 22 '15 at 13:00

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var a = document.getElementById("whatever").value;

// You can use any 3
+a; // Unary Operator
parseInt(a, 10); // parseInt with radix 10
Number(a);

answered Dec 22 '15 at 13:00

void

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score 0 · Answer 3 · answered Dec 22 '15 at 13:01

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you can use function parseInt(string) that Convert string into int .Now in your senario :- var weight_str = document.getElementByID("weight"); var weight_int = parseInt(weight_str);

this will give you the result.

answered Dec 22 '15 at 13:01

Shubham Akodiya

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How to get a number from HTML form and pass it to JavaScript?

3 Answers3