之前要把canvas先清除掉，不然刷新数据，还会有前面的图表

function clearCanvas(){
			$('#donutChart').remove();
			$('#chartdiv').append('<canvas id="donutChart" style="min-height: 500px; height: 500px; max-height: 500px; max-width: 70%;">  </canvas>');
			container=document.getElementById("donutChart");
			context=container.getContext("2d");
		}

 

function ShowDishGroupPie(PieData)
		{
			// [{"totalcount":0,"title":"菜品总条数","id":1,"per":0}]
			// alert(PieData.dbCount);
			// alert(JSON.stringify(PieData.dbData));
			// var length = Object.keys(PieData.dbData).length;
			var labels =[];
			var data = [];

			PieData.dbData.forEach(function(val, index) {
				if(val.title != '菜品总条数' && val.title != '平均用时(分钟)' && val.title != '传菜条数')
				labels.push( val.title);
			});
			PieData.dbData.forEach(function(val, index) {
				if(val.title != '菜品总条数' && val.title != '平均用时(分钟)' && val.title != '传菜条数')
				data.push( val.totalcount);
			});
		
			// for(i=0;i<PieData.dbCount - 1;i++)
			// {
			// 	alert(PieData.dbData)
			// }

			var ctx = document.getElementById("donutChart").getContext("2d");
 
			var data = {
				labels:labels,
				datasets: [
					{
						data: data,
						backgroundColor: [
							"#FF6384",
							"#36A2EB",
							"#FFCE56",
							"#00FF00",
							"#D2691E",
							"#00FFFF",
							"#FF00FF"
						],
						hoverBackgroundColor: [
							"#FF6384",
							"#36A2EB",
							"#FFCE56",
							"#00FF00",
							"#D2691E",
							"#00FFFF",
							"#FF00FF"
						]
					}]
			};

			pieOptions = {};


			var myPieChart = new Chart(ctx,{
				type: 'pie',
				data: data,
				options: pieOptions
			});
		}
	</script>