有的朋友可能对于“JS每日一题-小demo之JS实现通过键盘方向键操作图片上下左右无缝切换 js键盘上下左右事件”还有很多不明白的地方，下面由77ISP云服务器技术小编为大家讲解一下，下面我们来一起看看吧！

.wrap {
margin: 150px auto;
position: relative;
width: 400px;
height: 300px;
overflow: hidden;
border: 2px solid #000;
} 
.wrap img {
position: absolute;
}









(function(){
var data = ["https://www.php.cn/pic/1.jpg","https://www.php.cn/pic/2.jpg","pic/3.jpg","pic/4.jpg"];
var img = document.querySelectorAll('img');
var now = 0;
var next = 0;
var imgW = css(img[0],"width");
var imgH = css(img[0],"height");
var isMove = false;
document.addEventListener('keyup', function(e) {
if(isMove){
return;
}
switch(e.keyCode){
case 37:
//向左
toLeft();
break;
case 38:
//向上
toUp();
break;
case 39:
//向右
toRight();
break;
case 40:
//向下
toDown();
break; 
}
});
function toLeft(){
next = (now + 1)%data.length;
init([0,0,0,imgW],{left:-imgW},{left:0});
}
function toUp(){
next = (now + 1)%data.length;
init([0,0,imgH,0],{top:-imgH},{top:0});
}
function toRight(){
next = (now - 1 + data.length)%data.length;
init([0,0,0,-imgW],{left:imgW},{left:0});
}
function toDown(){
next = (now - 1 + data.length)%data.length;
init([0,0,-imgH,0],{top:imgH},{top:0});
}
// styles = [0,0,0,0];
// target1 {}
//init 初始位置
function init(styles,target1,target2){
isMove = true;
img[0].src= data[now];
img[1].src= data[next];
css(img[0],"top",styles[0]);
css(img[0],"left",styles[1]);
css(img[1],"top",styles[2]);
css(img[1],"left",styles[3]);
now = next;
move(img[0],target1);
move(img[1],target2,function(){
isMove = false;
});
}
// 移动
function move(el,target,callBack){
startMove({
el:el,
target:target,
type: "easeOut",
time: 1000
});
}
})(); 



//动画形式公式
var Tween = {
linear: function (t, b, c, d){
return c*t/d + b;
},
easeIn: function(t, b, c, d){
return c*(t/=d)*t + b;
},
easeOut: function(t, b, c, d){
return -c *(t/=d)*(t-2) + b;
},
easeBoth: function(t, b, c, d){
if ((t/=d/2)  d){
clearInterval(init.el.timer);
init.callBack&&init.callBack();
} else {
for(var s in init.target){
var val = Tween[init.type](t,b[s],c[s],d);
css(init.el,s,val);
}
}
},20);
}

以上就是“JS每日一题-小demo之JS实现通过键盘方向键操作图片上下左右无缝切换 js键盘上下左右事件”的详细内容，更多请关注77isp云服务器技术网其它相关文章！