JS1K是JavaScript编程竞赛——参加竞赛的规则很简单，脚本必须小于1K，竞赛网站开始也只是为了娱乐，却意外地收到了很多优秀的作品。
这是JS1k上传的作品，用几十行代码实现的一个3D旋转魔方：
代码如下：
function z(t, e) {
return t? e? t.appendChild(e) : "width:"+t+"px;height:"+t+"
px;position:absolute;" : document.createElement("div")
}
function w() {
++t==360&&(t=0, x=++x%3)
for (i in m) 2 == m[i][s[x]] ? m[i][u][a] = r+s[x]+"(" + t + "deg)" : 0;
c[u][a] = r+"3d(1,1,1," + t + "deg)",
requestAnimationFrame(w)
}
var a = "transform",
p = "background-color:",
y = a+"-style:preserve-3d;",
u = "style",
v = "cssText",
B = z(),
c = z(),
t = x = 0,
d, e, f, g, h, k, l, m = [], n, i, r="rotate", s = ["X","Y","Z"];
B[u][v] = "perspective:900px;"+z(600)+p+"#666";
c[u][v] = y + z(240) +"top:30%;left:30%", z(B, c), z(window.b, B);
for (l = 27; l--; z(c, f)) {
f = z(),
f[u][v] = y + z(240),
f.X = g = l % 3,
f.Y = h = (l - g) % 9 / 3,
f.Z = k = ~~(l / 9), e = z(),
e[u][v] = y + z(80) +a+":translate3d(" + 80 * g + "px," +
80 * h + "px," + 80 * (k-1) + "px)";
for (n = 6; n--; z(e, d))
d = z(),
d[u][v] = y + z(72) + "border-radius:9px;border:4px solid
#000;opacity:0.9;"+a+":"+r+"X(" + (4 > n ? 90 * n : 0)
+ "deg)"+r+"Y(" + (4 > n ? 0 : 4 == n ? -90 : 90) + "deg)translateZ(40px);"+p+
(0==n&&2==k?"#05C":1==n&&0==h?"#FD0":
2==n&&0==k?"#0A6":3==n&&2==h?"#FFF":4==n&&0==g?"#F60":5==n&&2==g?"#C24":"#000");
z(f, e), m.push(f)
}
w();
知识点扩展
JS如何实现旋转的魔方，浏览器从其他标签页回来依然匀速旋转？
Documentfrontbackleftrighttopbottom
.cube {
width: 400px;
height: 400px;
transition: all 3s;
margin: 300px auto;
/* 作用于所有3d转换的子元素 设置给父级 */
/* perspective: 1000px; */
/* transform: rotateX(30deg) rotateY(45deg); */
/* 平面到立方 默认值:平面flat*/
transform-style: preserve-3d;
position: relative;
}
/* div:hover {
transform: rotateY(90deg) translateZ(-200px);
opacity: 0.5;
} */
.front,
.back,
.left,
.right,
.top,
.bottom {
width: 100%;
height: 100%;
text-align: center;
line-height: 400px;
position: absolute;
opacity: 0.9;
left: 0;
top: 0;
}
.front {
background-color: palevioletred;
background-image: url('/tj/pics/hv1/117/208/2153/140051982.jpg');
transform: translateZ(200px);
}
.back {
background-color: yellow;
transform: translateZ(-200px);
background-image: url('/70cFuXSh_Q1YnxGkpoWK1HF6hhy/it/u=841408372,3004217725&fm=11&gp=0.jpg');
}
.left {
background-color: pink;
background-image: url('/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=2388632836,3966607624&fm=26&gp=0.jpg');
transform: rotateY(90deg) translateZ(-200px)
}
.right {
background-color: yellowgreen;
background-image: url('/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=192610795,467565159&fm=26&gp=0.jpg');
transform: rotateY(90deg) translateZ(200px)
}
.top {
background-color: skyblue;
background-image: url("/70cFuHSh_Q1YnxGkpoWK1HF6hhy/it/u=2936477803,4198185787&fm=15&gp=0.jpg");
transform: rotateX(90deg) translateZ(200px)
}
.bottom {
background-color: orange;
background-image: url('/pclady/1611/02/1612285_jyz.jpg');
transform: rotateX(90deg) translateZ(-200px)
}
window.onload = function () {
let cube = document.querySelector('.cube')
let timer = null
let x = 0; y = 0;
function rotate() {
cube.style.transform = 'rotateX(' + x + 'deg)' + '' + 'rotateY(' + y + 'deg)';
x += 30
y += 45
}
function stop() {
clearInterval(timer)
}
clearInterval(timer);
timer = setInterval(() => {
rotate();
}, 1000);
// 监听是否在当前页，并置为已读
// document.addEventListener("visibilitychange", function () {
// if (document.hidden) { //不处于当前页面
// // do something
// clearInterval(timer)
// } else {
// timer;
// }
// });
var hiddenProperty = 'hidden' in document ? 'hidden' :
'webkitHidden' in document ? 'webkitHidden' :
'mozHidden' in document ? 'mozHidden' :
null;
var visibilityChangeEvent = hiddenProperty.replace(/hidden/i, 'visibilitychange');
var onVisibilityChange = function () {
if (!document[hiddenProperty]) {
timer = setInterval(() => {
rotate();
}, 1000);
console.log(hiddenProperty);
} else {
clearInterval(timer)
}
}
document.addEventListener(visibilityChangeEvent, onVisibilityChange);
// document.addEventListener("visibilitychange", function () {
// if (!document.hidden) { //处于当前页面
// timer = setInterval(() => {
// rotate();
// }, 1000);
// console.log('active');
// } else {
// clearInterval(timer);
// console.log('hidden');
// }
// });
}
