下面贴了body的代码,要用列表,怎么出现多个圆?求解
<canvas width="640" height="480"></canvas>
<br><button id="btn"></button>
<script>
let circles=[];
let id=null;
let x=parseInt(Math.random()*640);
let y=parseInt(Math.random()*480);
let c={x,y,r:40};
const cv=document.querySelector("canvas");
const gc=cv.getContext("2d");
const btn=document.querySelector("#btn");
btn.addEventListener('click',()=>{
for(let i=0;i<circles.length;i++){
if(id==null){
id=setInterval(draw,7);
}
circles.push[i];
}
})
function draw(){
c.x +=1;
c.y +=1;
gc.clearRect(0,0,cv.width,cv.height);
gc.beginPath();
gc.lineWidth=5;
gc.strokeStyle="blue";
gc.arc(c.x,c.y,c.r,0,2*Math.PI);
gc.stroke();
}
</script>