Javascript String to int conversion

Question

I have the following JS immbedded in a page:

var round = Math.round;
var id = $(this).attr("id");

var len = id.length;
var indexPos = len -1; // index of the number so that we can split this up and used it as a title

var pasType = id.substring(0, indexPos); // adult, child or infant
var ind = round(id.substring(indexPos)); // converts the string index to an integer
var number = (id.substring(indexPos) + 1); // creates the number that will go in the title
window.alert(number);

id will be something like adult0, and I need to take that string and split it into adult and 0 - this part works fine.

The problem comes in when I try to increment the 0. As you can see I use Math.round to convert it to an integer, and then add 1 to it - I expect 0 to be 1 after this. However, it doesn't seem to be converting it to integer, because I get 01, not 1. When testing this with adult1 the alert I get is 11.

I'm using this question for reference, and have also tried var number += id.substring(indexPos);, which breaks the JS (unexpected identifier '+=')

Does anyone know what I'm doing wrong? Is there a better way of doing this?

question from:https://stackoverflow.com/questions/18713508/javascript-string-to-int-conversion

Answer 1

The parseInt() function parses a string and returns an integer,10 is the Radix or Base [DOC]

var number = parseInt(id.substring(indexPos) , 10 ) + 1;