// JavaScript Document

    var current_world_population = 6935684213;
    var current_agricultural_land = 8498691007;
    var increment_world_population = +1.5*150/60; // +150/minute
    var increment_agricultural_land = -0.1; // -6/minute
	var current_forest_land = 9516485;
	var increment_forest_land = 15/42;
    var period_world_population = 1500; //milliseconds
    var period_agricultural_land = 1000; //milliseconds
	var period_forest_land = 1000; //milliseconds

    window.addEvent('domready', function() {
        // activate language selector
        this.update_population = function(){
            current_world_population = current_world_population + increment_world_population;
            $('world_population').innerHTML = formatNumber(current_world_population,0);
			$('world_population').tween('color', '#AAA', '#8F8F8F');
        }
       
        this.update_land = function(){
            current_agricultural_land = current_agricultural_land + increment_agricultural_land;
            $('agricultural_land').innerHTML = formatNumber(current_agricultural_land,1) + ' ha.';
			$('agricultural_land').tween('color', '#AAA', '#8F8F8F');
        }
       
	    this.update_forest = function(){
            current_forest_land = current_forest_land + increment_forest_land;
            $('forest_land').innerHTML = formatNumber(current_forest_land,1) + ' ha.';
			$('forest_land').tween('color', '#AAA', '#8F8F8F');
        }
      
        this.formatNumber = function(nStr, decimal_places)
        {
            // round number
			nStr = nStr.toFixed(decimal_places);
           
            // add commas
            nStr += ''; // convert to string
            var x = nStr.split('.');
            var x1 = x[0];
            var x2 = x.length > 1 ? '.' + x[1] : '';
            var rgx = /(\d+)(\d{3})/;
            while (rgx.test(x1)) {
                x1 = x1.replace(rgx, '$1' + ',' + '$2');
            }
            return x1 + x2;
        }

       
       
        // start updates
        update_population();
        update_land();
		update_forest();
        update_population.periodical(period_world_population);
        update_land.periodical(period_agricultural_land);
		update_forest.periodical(period_forest_land);
    });