add using jquery

Question

I want to do this

var x=$(this).attr('id');
var y = x+1;

where x is an integer

but the value I get is x1

How do I do get the 16, if x=15?

Thanks Jean

id, should not start with numbers... – Reigel Gallarde Jul 07 '10 at 11:16 — Reigel Gallarde, Jul 07 '10 at 11:16
http://www.w3.org/TR/html401/types.html#type-name – LukeH Jul 07 '10 at 11:23 — LukeH, Jul 07 '10 at 11:23

score 8 · Answer 1 · edited May 23 '17 at 12:03

8

All the answers so far are missing the radix parameter

var x=parseInt($(this).attr('id'), 10);
var y = x+1;

edited May 23 '17 at 12:03

Community

answered Jul 07 '10 at 11:12

Dan F

2

That's because it's an optional parameter and defaults to 10. – Dave Markle Jul 07 '10 at 11:24
3

@Dave: So what value do you think `parseInt('0123')` might return? https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Functions/parseInt – LukeH Jul 07 '10 at 11:35
1

@Dave - Yes, optional, defaults to 10, [unless the string starts with 0](http://www.w3schools.com/jsref/jsref_parseInt.asp). It's a deprecated feature, but it still [bites](http://www.kipras.com/a-fact-about-javascript-parseint-that-i-wasnt-aware-of/105) [people](http://www.mgitsolutions.com/blog/2008/10/07/the-importance-of-the-javascript-parseint-radix/). My copy of chrome even does the deprecated thing, using [this test](http://jehiah.cz/archive/javascript-parseint-is-broken). – Dan F Jul 07 '10 at 11:39
1

@LukeH: Thanks for the article. Javascript strikes again. That's *awful*. – Dave Markle Jul 07 '10 at 11:47

score 2 · Accepted Answer · answered Jul 07 '10 at 11:08

2

var y = parseInt(x) + 1;

should do the trick.

answered Jul 07 '10 at 11:08

Andrew

score 1 · Answer 3 · answered Jul 07 '10 at 11:09

1

You need to tell JavaScript it's an integer using parseInt

var y = parseInt(x) + 1;

answered Jul 07 '10 at 11:09

Mark Elliot

score 1 · Answer 4 · answered Jul 07 '10 at 11:28

1

console.log(Number("23") + 1);   //24

I think you should be using Number() instead of parseInt because:

console.log(Number("23#") + 1);   //NaN
console.log(parseInt("23#") + 1); //24 (I would expect a NaN)

answered Jul 07 '10 at 11:28

Amarghosh

4 Answers4