Using mouse coordinates as pixel values for javascript functions

Question

Is there any way to input mouse click coordinates as the amount by which to change an element property as in the following sort of function? Specifically is there a way to use the Y coordinate of the mouse click as the pixel amount for the height instead of a fixed pixel number?

function changeObject() {
    document.getElementById('object').style.height = '500px';
}

Edit:

Use cookies to remember former height

<script type="text/javascript">
function setCookie (name, value, expires, path, domain, secure) {
    document.cookie = name + "=" + escape(value) +
    ((expires) ? "; expires=" + expires : "") +
    ((path) ? "; path=" + path : "") +
    ((domain) ? "; domain=" + domain : "") +
    ((secure) ? "; secure" : "");
}
function getCookie (name) {
    var cookie = " " + document.cookie;
    var search = " " + name + "=";
    var setStr = null;
    var offset = 0;
    var end = 0;
    if (cookie.length > 0) {
        offset = cookie.indexOf(search);
        if (offset != -1) {
            offset += search.length;
            end = cookie.indexOf(";", offset);
            if (end == -1) {
                end = cookie.length;
            }
            setStr = unescape(cookie.substring(offset, end));
        }
    }
    if (setStr == 'false') {
        setStr = false;
    } 
    if (setStr == 'true') {
        setStr = true;
    }
    if (setStr == 'null') {
        setStr = null;
    }
    return(setStr);
}
  document.getElementById('bookmarktag').onclick = function(event){
    var clickX = event.clientX + document.body.scrollLeft;
      var clickY = event.clientY + document.body.scrollTop; 

    document.getElementById('bookmark').style.height = clickY + 'px';
    document.getElementById('bookmark2').style.marginTop = clickY + 'px';

    document.getElementById('bookmarkdiv2').style.display = 'block';
    document.getElementById('bookmarkdiv').style.display = 'none';

    setCookie('bookmark_state', true);
}  

function checkBookmark() {
    if (getCookie('bookmark_state') == null) {
        document.getElementById('bookmarkdiv').style.display = 'block';
    }   
    if (getCookie('bookmark_state') == true) {
            document.getElementById('bookmark').style.height = clickY + 'px';
            document.getElementById('bookmark2').style.marginTop = clickY + 'px';

            document.getElementById('bookmarkdiv2').style.display = 'block';
            document.getElementById('bookmarkdiv').style.display = 'none';
    }  
}
</script>

Answer 1

try this for relative to document

document.getElementById('someElement').onclick = function(event){
    var clickX = event.clientX + document.body.scrollLeft;
    var clickY = event.clientY + document.body.scrollTop;

    document.getElementById('object').style.height = clickY + 'px';
}