这串代码没有问题

aneObj.prototype.draw=function(){

ctx2.save();

ctx2.globalAlpha=.6;

for(var i = 0;i<this.num;i++){

//beginPath,moveTo,lineTo,stroke,strokeStyle,lineWidth,lineCap,globalAlpha

ctx2.beginPath();

ctx2.moveTo(this.x[i],canHeight);

ctx2.lineTo(this.x[i],canHeight-this.len[i]);

ctx2.lineWidth=20;

ctx2.lineCap='round'

ctx2.strokeStyle="#3b154e";

ctx2.stroke();

}

ctx2.restore();

}