Simple math addition in JS giving wrong result

Question

I have this strange problem I can't get my head around. I try to find the highest number in a list of elements which have a data-index attribute for their respective number. But when iterating over them, JS insists that 9 < 10 is false.
See this fiddle: http://jsfiddle.net/1ztbxbjx/

What I'm doing wrong?

I can't use

for (i = 0; i < $('div[data-index]'; i++))

Sometimes there will be numbers out of order in the list (eg. 1,2,3,4,5,25,31).

those indexes are returning strings. they are not true numbers you will need to convert the string to a number. — Cayce K
– Cayce K, Commented Jun 29, 2015 at 15:07

depperm · Accepted Answer · 2015-06-29 15:09:20Z

2

You need to parse the id, otherwise you're comparing strings. Here is an example using parseInt()

edited Jun 29, 2015 at 15:09

answered Jun 29, 2015 at 15:07

depperm

10.8k4 gold badges46 silver badges68 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Cayce K Over a year ago

couldn't remember the function off top my head so didn't want to do an answer. kudos to you

Sachin Thapa · Accepted Answer · 2015-06-29 15:19:58Z

Parse retreived id to Number and it should work fine, try this:

var current = Number($(this).attr('id'));

Tested in JSFiddle, its working fine after this one line change.

Cheers !

Mike Cluck · Accepted Answer · 2015-06-29 16:06:59Z

1

Use this

if (indexCount < parseInt(current)) {

instead of

if (indexCount < current) {

edited Jun 29, 2015 at 16:06

Mike Cluck

32.6k13 gold badges84 silver badges95 bronze badges

answered Jun 29, 2015 at 15:13

Omkar Kulkarni

8247 silver badges12 bronze badges

Collectives™ on Stack Overflow

Simple math addition in JS giving wrong result

3 Answers 3

1 Comment

Comments

Comments

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Related