滚轮事件
- 当鼠标滚轮滚动时,JavaScript可以监听到,称之为滚轮事件
- Chrome,IE:DOM0级事件
onmousewheel
wheelDelta 120表示向上 -120表示向下
- Firefox:DOM2级事件
DOMMouseScroll
detail 3表示向下 -3表示向上
document.addEventListener('DOMMouseScroll', function (e) {
console.log(e);
console.log(e.detail);
});
document.onmousewheel = fun;
document.addEventListener('DOMMouseScroll', fun);
function fun (e) {
var direction;
e = e || window.event;
if (e.wheelDelta) {
if (e.wheelDelta > 0) {
direction = -1;
} else {
direction = 1;
}
} else {
if (e.detail > 0) {
direction = 1;
} else {
direction = -1;
}
}
console.log(direction);
}
拖拽
var box = document.getElementById('box');
box.onmousedown = function (e) {
e = e || window.event;
var deltaX = e.clientX - box.offsetLeft;
var deltaY = e.clientY - box.offsetTop;
document.onmousemove = function (e) {
e = e || window.event;
box.style.left = e.clientX - deltaX + 'px';
box.style.top = e.clientY - deltaY + 'px';
}
}
document.onmouseup = function () {
document.onmousemove = null;
}