jQuery Text field containing math operator

Question

I have several text fields, and the value of these fields can be "4", "-2", "10", etc.

I would like to retrieve this value and make the corresponding mathematical operation:

var price = 50;
var value = $ ( "# myTextField").val(); //e.g value = "+50"
var finalprice = price + value

alert(finalprice)

But, of course it doesnt work and only display "50+50". Could you please help me so it can also work if my value was -30 ? Thanks a lot

EDIT: Sorry but you didn't understand me: I need to keep the math operator of my text field (- or +) so I can't convert my string into an Integer.

Use var value = parse.int($ ( "# myTextField").val()); – Venkata Krishna Reddy Oct 13 '16 at 15:10 — Venkata Krishna Reddy, Oct 13 '16 at 15:10
Tl;Dr `Number($( "#myTextField").val());` – Liam Oct 13 '16 at 15:10 — Liam, Oct 13 '16 at 15:10

score 2 · Answer 1 · edited Oct 13 '16 at 15:13

2

you need to parse string to an integer:

var value = parseInt($("#myTextField").val(), 10);

edited Oct 13 '16 at 15:13

A. Wolff

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answered Oct 13 '16 at 15:11

Alexander Paschenko

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Thx for the radix ;) – A. Wolff Oct 13 '16 at 15:11
2

Watch the spaces `"#myTextField"` !== `"# myTextField"` – Liam Oct 13 '16 at 15:12
No, I don't want to convert my string in Int, because the value contains the math operator I need (+10 or -4) – Yoyo Oct 13 '16 at 15:14
If u convert -10 to parseInt("-10") it will return -10 it will not make 10 – Venkata Krishna Reddy Oct 13 '16 at 15:30

Adrian C. · Answer 2 · 2016-10-13T16:00:27.830

0

You should parse the string as integer - parseInt() https://jsfiddle.net/wk4a5vm2/1/

If you want to get string with an operator you should use eval() https://jsfiddle.net/wk4a5vm2/4/

edited Oct 13 '16 at 16:00

answered Oct 13 '16 at 15:12

Adrian C.

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jQuery Text field containing math operator

2 Answers2