javascript实现勾股定理

var points=[];
points[0]={};
points[0].x=0;
points[0].y=0;
points[1]={};
points[1].x=3;
points[1].y=4;
points.dist=function(){
    var p1=this[0];
    var p2=this[1];
    var a=p2.x-p1.x;
    var b=p2.y-p1.y;
    return  Math.sqrt(a*a+b*b);
}