Question : from X and Y cordites when changing & moving

from X and Y cordites how to find nearest to me as the crow flys
when the points are changing ie moving

Answer : from X and Y cordites when changing & moving

Try like this:
var X1=0,Y1=0,X2=0,Y2=0, iDistance=0

function Clicked()
{
  if (X1)
  {
    X2=window.event.clientX
    Y2=window.event.clientY
  }
  else
  {
    X1=window.event.clientX
    Y1=window.event.clientY
  }
  If (X2)
  {
    iDistance=sqrt(square(X1-X2)+square(Y1-Y2))
    X1=X2
    Y1=Y2
    document.write("iDistance")
  }
}

Call Clicked() from the mouseclick event of your page. This will calculate distance between click1 and click2, then, when you click a 3rd time, between 2nd and 3rd, etc. Something like this anyway.