javascript adding variables on top

Question

Okay this should be a simple one

            var width1 = size3 + 275 ; // adding more
            var width2 = 225 - size1; // subtracting width

width2 is coming out fine, for example if size1 = 4 width2 = 221. However if size3 is 4 the width1 comes out 4275. It keeps adding it to the front or back. I don't know why. ( I have flipped the size3 + 275, back and forth {275+size3} even put '275' in quotes.

Thanks for your help

common problem. You're adding to a string. Use +size3 + 275 — Dave
– Dave, Commented Apr 10, 2013 at 22:54
Or you could multiply it by 1, var width1 = size3 * 1 + 275. I don't know which method has least overhead... — Coin_op
– Coin_op, Commented Apr 10, 2013 at 23:01

Matt Zeunert · Accepted Answer · 2013-04-10 22:54:31Z

3

The size value is treated as a string because it's in quotes, use parseInt to turn it into an integer:

var width1 = parseInt(size3, 10) + 275 ; // adding more
var width2 = 225 - parseInt(size1, 10); // subtracting width

If size is a string the + operator is used to concatenate rather than add.

answered Apr 10, 2013 at 22:54

Matt Zeunert

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1 Comment

WackyMole Over a year ago

Thanks you very much. Was thinking something like that. Although I did not know parseInt could fix it.

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