Javascript 用区间存储随机数组值
我如何用白色/无背景替换旧的“盒子”Javascript 用区间存储随机数组值,javascript,Javascript,我如何用白色/无背景替换旧的“盒子” var counter = 11; var check = 0; var boxes = ["box_1","box_2","box_3","box_4"]; clock = setInterval(function() { counter--; if(counter==0) { clearInterval(clock); document.getElementById("counter").innerHTM
var counter = 11;
var check = 0;
var boxes = ["box_1","box_2","box_3","box_4"];
clock = setInterval(function() {
counter--;
if(counter==0) {
clearInterval(clock);
document.getElementById("counter").innerHTML="Time Left: 0 seconds.";
} else {
var box = boxes[Math.floor(Math.random()*boxes.length)];
document.getElementById("counter").innerHTML="Time Left: " + counter.toString() + " seconds.";
document.getElementById(box).style.backgroundColor="#000";
}
}, 1000);
我试图将该框存储为old\u-box
->old\u-box=box
,但它不起作用
人们似乎在误解。
我想存储框值,以便在下一个循环中调用它并将其设置为白色,而新框可以设置为黑色。您需要记住框:
var counter = 11;
var check = 0;
var boxes = ["box_1","box_2","box_3","box_4"];
var lastbox = false;
clock = setInterval(function() {
counter--;
if(counter==0) {
clearInterval(clock);
document.getElementById("counter").innerHTML="Time Left: 0 seconds.";
} else {
if (lastbox) {
document.getElementById(lastbox).style.backgroundColor = "#FFF";
}
lastbox = boxes[Math.floor(Math.random()*boxes.length)];
document.getElementById("counter").innerHTML="Time Left: " + counter.toString() + " seconds.";
document.getElementById(lastbox).style.backgroundColor="#000";
}
}, 1000);
只需将元素的背景设置为#000
哪个索引与随机数(r==i)
或者,如果您想使用广泛的选择器获取更多元素:(较慢)
#000是黑色而不是白色。您的标题似乎与您的主题无关question@DJL你误会了。我想把旧盒子调成白色,把新盒子调成黑色。你真是个天才,我的朋友!至少有人理解了询问的内容。您需要定义变量
clock
。
function $id(_) { return document.getElementById(_); }
function $el(_) { return document.querySelectorAll(_); }
function game() {
if (!c) clearInterval( clock );
$cou.innerHTML = "Time Left: "+ (c--) +" seconds.";
var r = ~~(Math.random()*n);
for(var i=0; i<n; i++) $box[i].style.backgroundColor = i==r?"#000":"#fff";
}
var $box = $el("[id^=box_]"),
$cou = $id("counter"),
n = $box.length,
c = 10,
clock = setInterval(game, 1000);
$id("elementID")
$el(".elements") // [] array collection
$el("[id^=prefix]") // [] array collection
$el("input") // [] array collection