js 兩點間距離函數

var points = [{x:0,y:0},{x:1,y:1}];
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);
    }; 
points.dist()