chat.js无法画出Y轴数据

Question

动态获取数据之后，无法画出Y轴信息，浏览器没有报错。浏览器打印是有数据的，新手学习。

window.onload=function()
{

getdatafromDB();  

}

var getdatafromDB = function(){

$.ajax({  
    url: "./line.php",  
    type: "POST",  
    dataType:"json",  
    error: function(){    
         alert('Error loading XML document');    
    }, 
    success:function(data){
        bar(data);  
    }  
});  

}

function bar(Data)
{

if(Data.length == null || Data.length == 0)  
{
    return;
}

var lineChartData={};  
lineChartData.labels=[];  
lineChartData.datasets=[];

var temData={};  
temData.data=[];  
temData.fillColor= "rgba(220,220,220,0.5)";  
temData.strokeColor = "rgba(220,220,220,1)";  
temData.pointColor="rgba(220,220,220,1)",  
temData.pointStrokeColor= "#fff";  

for(var i=0;i<Data.length;i++)  
{
    lineChartData.labels.push(Data[i]['lable']);  
    temData.data.push(Data[i]['value']);  
}

lineChartData.datasets.push(temData);
console.log(lineChartData);

var myLine = new Chart(document.getElementById("canvas").getContext("2d")).Line(lineChartData,{
    responsive:true
});

}