root/trunk/website/blog/cfformprotect/js/mouseMovement.js @ 5

/* This code will grab two mouse coordinate sets from the user's mouse.
 * The first set is shortly after the user starts moving thier mouse across the web page.
 * The second set is grabbed a specified time later.  The distance between the two sets
 * is calculated and stored in a form field
 */

//tell the browser to start executing the timedMousePos function every x milliseconds
var myInterval = window.setInterval(timedMousePos,250)

// Variables for mouse positions
var xPos = -1;
var yPos = -1;
var firstX = -1;
var firstY = -1;
// variable to track how many times I polled the mouse position
var intervals = 0;

// retrieve mouse x,y coordinates
function getMousePos(p) {
        if (!p) var p = window.event;
        if (p.pageX || p.pageY) {
                xPos = p.pageX;
                yPos = p.pageY;
        }       else if (p.clientX || p.clientY) {
                xPos = p.clientX + document.body.scrollLeft     + document.documentElement.scrollLeft;
                yPos = p.clientY + document.body.scrollTop + document.documentElement.scrollTop;
        }
}

// capture mouse movement
function timedMousePos() {
        //when the user moves the mouse, start working
        document.onmousemove = getMousePos;
        if (xPos >= 0 && yPos >= 0) {
                //0,0 is a valid mouse position, so I want to accept that.  for this reason
                //my vars are initialized to -1
                var newX = xPos;
                var newY = yPos;
                intervals++;
        }
        if (intervals == 1) {
                //store the first coordinates when we've got a pair (not when 'intervals' is 0)
          firstX = xPos;
        firstY = yPos;
        } else if (intervals == 2) {
                //I've got two coordinate sets
                //tell the browser to stop executing the timedMousePos function
        clearInterval(myInterval);
                //send the 4 mouse coordinates to the calcDistance function
        calcDistance(firstX,firstY,newX,newY);
  }
}

function calcDistance(aX,aY,bX,bY) {
        //use the Euclidean 2 dimensional distance formula to calculate the distance 
        //in pizels between the coordinate sets 
        var mouseTraveled = Math.round(Math.sqrt(Math.pow(aX-bX,2)+Math.pow(aY-bY,2)));
        //ajax stuff to set a session variable
        try     {
                // Dave Shuck - 26 Mar 2007 - added try/catch for giant pages that take a while to 
                // load, in case the user moves their mouse before the page is completely rendered.
                document.getElementById("formfield1234567891").value = mouseTraveled;
        }
        catch(excpt) { /* no action to take */ }
}

function dummy() {}