1 var lastx = 0;

     2 var lasty = 0;

     3 

     4 WorkerScript.onMessage = function(message) {

     5     var ydiff = message.y - lasty;

     6     var xdiff = message.x - lastx;

     7 

     8     var total = Math.sqrt(ydiff * ydiff + xdiff * xdiff);

     9 

    10     lastx = message.x;

    11     lasty = message.y;

    12 

    13     WorkerScript.sendMessage( {xmove: xdiff, ymove: ydiff, move: total} );

    14 }

    15