Instead of duplicating code do this:
function FirefoxMouseMove(e) {
HandleMouseMove(e.pageX, e.pageY);
}
function ChromeMouseMove(e){
HandleMouseMove(e.clientX, e.clientY);
}
function HandleMouseMove(x,y) {
document.getElementById("x").innerHTML="clientX: "+x;
document.getElementById("y").innerHTML="clientY: "+y;
}
Sorry I cannot help more than that, but hopefully it's better than nothing..

Find content
Not Telling