Capture true position of mouse

How do you capture the TRUE position of the mouse in an html document with javascript? I tried using event.y for the Y coordinate, but the value doesn't increase when you scroll down the page. Thanks.
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Pravin AsarPrincipal Systems EngineerCommented:
you need to add document.scrollOffsetX document.scrollOffsetY to  mouse co-ordinates to
get it's position from top-left of the page.
rbichonAuthor Commented:
document.scrollOffsetY comes up undefined.
Ultimate Tool Kit for Technology Solution Provider

Broken down into practical pointers and step-by-step instructions, the IT Service Excellence Tool Kit delivers expert advice for technology solution providers. Get your free copy now.

rbichonAuthor Commented:
How do I get the height of the viewable window?
Pravin AsarPrincipal Systems EngineerCommented:
<title>Window and Screen Size Details</title>
<body onscroll="reLocateDiv();">
<script language="javascript">
var wLeft = 0;
var wTop  = 0;
var wWidth=800;
var wHeight=600;
var scrWidth=0;
var scrHeight=0;

var wndDetail = new GetWindowDetails();
alert ('Screen Resolution : ' + wndDet.sWidth + ' X ' + wndDet.sHeight);
alert ('Window Location   : ' + wndDet.wLeft + ' , ' + wndDet.wTop);
alert ('Window Size       : ' + wndDet.wWidth + ' X ' + wndDet.wHeight);

function GetWindowDetails () {
this.wWidth = wWidth;
this.wHeight = wHeight;
this.sWidth = scrWidth;
this.sHeight = scrHeight;
this.wLeft = wLeft;
this.wTop  = wTop;
return this;
// Get Window Size
function WindowSize()
     if( typeof( window.innerWidth ) == 'number' ) {
          wWidth = window.innerWidth;
          wHeight = window.innerHeight;
     else if( document.documentElement &&
              (document.documentElement.clientWidth ||
               document.documentElement.clientHeight ) ) {
          //IE 6+ in 'standards compliant mode'
          wWidth = document.documentElement.clientWidth;
          wHeight = document.documentElement.clientHeight;
     else if( document.body && 
              (document.body.clientWidth ||
                 document.body.clientHeight ) ) {
          //IE 4 compatible
          wWidth = document.body.clientWidth;
          wHeight = document.body.clientHeight;

// Get Window Height
function GetWindowHeight () {
     return (wHeight-20);

// Get Window Width
function GetWindowWidth () {
     return (wWidth);

// Get Screen Resolution

function GetScreenResolution () {
   scrWidth = window.screen.width;
   scrHeight = window.screen.height;

// Get Window Location
function GetWindowLocation () {
    if (!document.layers && document.all) {
          wLeft = window.screenLeft;
          wTop = window.screenTop;
    else {
          wLeft = window.screenX;
          wTop  = window.screenY;

function resizeDiv()
   var wndDetail = new GetWindowDetails();
   var newWidth=wndDetail.wWidth - 100;
   if (newWidth>1000) newWidth=1000;

function rePositionDiv()
   var wndDetail = new GetWindowDetails();
   var divObj = document.getElementById("divMainContent");
   var newX= (parseInt (wndDetail.wWidth) - parseInt(; = parseInt(newX);
   var newY= (parseInt (wndDetail.wHeight) - parseInt(; = parseInt(newY);


function reLocateDiv () {
   var wndDetail = new GetWindowDetails();
   var divObj = document.getElementById("divMainContent");
   var newY= parseInt(orgPosY) +  parseInt (window.document.body.scrollTop);
   var newX= parseInt(orgPosX) +  parseInt (window.document.body.scrollLeft);
   window.status = newY + ' , ' + window.document.body.scrollTop; =  parseInt(newY); = parseInt(newX);
var divObj  = document.getElementById("divMainContent");
var orgPosY = 10;
var orgPosX = 10;
<span id="divMainContent" style="border: 1px solid black; position: absolute; top: 10px; left: 10px; width: 50px; height: 100px;">DIV OBJECT</span>
<div style="height: 1000px; width: 1000px; ">DIV</div>


Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.