html('');


        } else { //this part of content will shall when it's on us heatmap

          $("#rankingToggle").css('visibility', 'visible');
          $("#content-explain").text(
            "This situational heatmap (Beta) illustrates the rank of active confirmed cases in all countries or U.S. states in the descending order. It uses a series of blocks in different size and color to represent the number and recover rate of coronavirus cases of different places within the last 20 days. The size of the