if number is between two numbers by plus/minus 10 addclass

Question

http://jsfiddle.net/kM8xE/2/

If I have the divs ​

<div class="value">15</div>
<div class="value2">20</div>​

and jQuery

var actual = $(".value").html();
var comparison = $(".value2").html();

how can i add class .isbetween to .value2 if it's html value is between +/-10 of the html for .value ie. for this eg. a value between 5 and 25.

I am not too good but i have tried and it doesn't work.

if(parseInt(actual)-10 <= parseInt(comparison) <= parseInt(actual)+10){
$(".value2").addClass("isbetween");
}

Answer 1

 if (Math.abs(actual - comparison) <= 10) {
    //they're within 10
 }

Answer 2

The reason this doesn't work is that you can't chain comparisons like this:

5 < x < 10

In Javascript (and other languages with c-like syntax), you have to make two separate comparisons, and use the boolean and operator (&&) to chain the comparisons together:

var actualValue = parseInt(actual);
var comparisonValue = parseInt(comparison);

if(actualValue - 10 <= comparisonValue && comparisonValue <= actualValue + 10) {
    $(".value2").addClass("isbetween");
}

Also, don't repeat yourself. Do the conversion once, and store it in a local variable. This makes the code much more readable.

This can be made even more simple by using a concept called absolute value. Then you can just do your difference, and see if its absolute value is less than or equal to ten.

var delta = Math.abs(parseInt(actual) - parseInt(comparison));

if(delta <= 10) {
    $(".value2").addClass("isbetween");
}