How to increment a numeric string by +1 with Javascript/jQuery

Question

I have the following variable:

pageID = 7

I'd like to increment this number on a link:

$('#arrowRight').attr('href', 'page.html?='+pageID);

So this outputs 7, I'd like to append the link to say 8. But if I add +1:

$('#arrowRight').attr('href', 'page.html?='+pageID+1);

I get the following output: 1.html?=71 instead of 8.

How can I increment this number to be pageID+1?

Answer 1

Try this:

parseInt(pageID, 10) + 1

Accordint to your code:

$('#arrowRight').attr('href', 'page.html?='+ (parseInt(pageID, 10) + 1));

Answer 2

+ happens to be valid operator for both strings and numbers that gives different results when both arguments are numeric and when at least one is not. One of possible workarounds is to use operator that only have numeric context but gives same mathematical result, like -. some_var - -1 will always be same as adding 1 to some_var's numeric value, no matter if it is string or not.

$('#arrowRight').attr('href', 'page.html?='+ (pageID - -1));