I have an array of numbers, for example [300, 500, 700, 1000, 2000, 3000] and I want to find the closest number, without going under the number given.

For instance, searching for 2200 would return 3000 (NOT 2000).

However, if I search for 3200 as there is nothing higher in the array, it should return 3000 as there are no other choices.

I can get the closest number that is under the value using:

if (sizeToUse == null || Math.abs(this - monitorWidth) < Math.abs(sizeToUse - monitorWidth)) {

                sizeToUse = this;

            }

However, I can't get the whole thing to work. My full code is:

$(function() {



var monitorWidth = window.screen.availWidth,

    sizeToUse = null,

    upscaleImages = false;



$('.responsive-img').each(function(){



    var sizeData = $(this).attr('data-available-sizes');

    sizeData = sizeData.replace(' ', '');



    var sizesAvailable = sizeData.split(',');

    sizesAvailable.sort(function(a, b){return b-a});



    $.each(sizesAvailable, function(){

        if(upscaleImages){

            if (sizeToUse == null || Math.abs(this - monitorWidth) < Math.abs(sizeToUse - monitorWidth)) {

                sizeToUse = this;

            }

        }

        else{

            //We don't want to upscale images so we need to find the next highest image available

        }



    });



    console.log('Size to use ' + sizeToUse + ' monitor width ' + monitorWidth);



});





});