JS:captureMouse

captureMouse.js

//当事件触发时,获取鼠标相对于元素的坐标
function captureMouse(elem) {
    var obj = {x:0,y:0};
    elem.addEvent("click", function(e) {
        var x, y;
        var event = e || window.event,
            element = event.currentTarget;

        //获取鼠标位于当前屏幕的位置， 并作兼容处理
        if (event.pageX || event.pageY) {
            x = event.pageX;
            y = event.pageY;
        } else {
            x = event.clientX + document.body.scrollLeft + document.documentElement.scrollLeft;
            y = event.clientY + document.body.scrollTop + document.documentElement.scrollTop;
        }
        //将当前的坐标值减去元素的偏移位置，即为鼠标位于当前canvas的位置
        x -= element.offsetLeft;
        y -= element.offsetTop;
        obj.x = x;
        obj.y = y;
    });
    return obj;
}