JS获取鼠标坐标的实例方法

var restrictX; 
var restrictY; 
var tip; 
// 鼠标坐标  
function mousePosition(ev){ 
    var scrollLeft = document.documentElement.scrollLeft || document.body.scrollLeft; 
    var scrollTop = document.documentElement.scrollTop || document.body.scrollTop; 
    return { 
        x:ev.clientX + scrollLeft - document.documentElement.clientLeft, 
        y:ev.clientY + scrollTop - document.documentElement.clientTop 
    }; 
} 
// 鼠标事件  
function mouseMove(ev){ 
    ev = ev || window.event; 
    var mousePos = mousePosition(ev); 
    restrictX = mousePos.x; 
    restrictY = mousePos.y; 
} 
document.onmousemove = mouseMove; 
document.onclick = mouseMove;