计算出圆的周长和面积 function circle(r) { this.r=r this.Area=Area this.Circum=Circum } function Circum() { return(3.14*2*this.r) } function Area() { return(3.14*this.r*this.r) } r=parseInt(prompt("请输入半径:","")); var newcircle=new circle(r) var Circumcapital=newcircle.Circum var Areacapital=newcircle.Area document.write("周长:"+newcircle.Circum+" ") document.write("面积:"+newcircle.Area+" ")