$(document).ready(function(){

  var mc = {

    '0-19'     : 'red',

    '20-59'    : 'orange',

    '60-100'   : 'green'

  };

function between(x, min, max) {

  return x >= min && x <= max;

}

​

  var dc;

  var first; 

  var second;

  var th;

  $('p').each(function(index){

    th = $(this);

    dc = parseInt($(this).attr('data-color'),10);

      $.each(mc, function(name, value){

        first = parseInt(name.split('-')[0],10);

        second = parseInt(name.split('-')[1],10);

        console.log(between(dc, first, second));

        if( between(dc, first, second) ){

          th.addClass(value);

        }

​

      });

  });

});