    function draw()   
      {  
          var canvas = document.getElementById("canvas");  
          if (canvas.getContext)  
          {  
            var context = canvas.getContext("2d");  
      
            context.fillStyle = "rgb(256,0,0)";  
            context.fillRect (15, 10, 55, 50);  
              
            context.fillStyle = "rgba(0, 0, 200, 0.6)";  
            context.fillRect (35, 30, 55, 50);  
          }  
      }  