Javascript红绿灯
Javascript红绿灯
提问于 2017-04-25 01:51:07
<!DOCTYPE>
<html>
<body>
<img id="traffic" src="assets/red.gif">
<button type="button" onclick="ChangeLights()">Change Lights</button>
<script>
var lights = [
"assets/red.gif",
"assets/yellow.gif",
"assets/green.gif",
"assets/yellow.gif",
];
var index = 0;
function ChangeLights() {
setInterval(function () {ChangeLights();}, 1000);
index = index + 1;
if (index == lights.length) index = 0;
var image = document.getElementById('traffic');
image.src=lights[index];
}
</script>
</body>
</html>
嗨，我正在尝试用JavaScript制作一个动画脚本，这样一旦按下按钮，红绿灯序列就会从定时器上的红-黄-绿-黄改变。我只想让序列循环一次。但是，当我在函数中实现setInterval函数时，灯只从红-黄-绿-红改变。谢谢你的帮助！
回答 5
Stack Overflow用户
发布于 2017-04-25 02:26:57
var lights = {
red: "https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Traffic_lights_red.svg/200px-Traffic_lights_red.svg.png",
yellow: "https://upload.wikimedia.org/wikipedia/commons/thumb/1/19/Traffic_lights_yellow.svg/200px-Traffic_lights_yellow.svg.png",
green: "https://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Traffic_lights_dark_green.svg/200px-Traffic_lights_dark_green.svg.png"
};
var sequence = ['red', 'yellow', 'green', 'yellow'];
function startChangeLights() {
for (var index = 0; index < sequence.length; index++) {
changeLight(index, sequence[index]);
}
function changeLight(index, color) {
setTimeout(function() {
var image = document.getElementById('traffic');
image.src = lights[color];
}, index * 1000);
}
}<div>
<img height=100px id="traffic" src="https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Traffic_lights_red.svg/200px-Traffic_lights_red.svg.png">
</div>
<div>
<button type="button" onclick="startChangeLights()">Change Lights</button>
</div>
Stack Overflow用户
发布于 2017-04-25 02:00:25
如果你正在寻找一个时间序列，你必须在javascript中使用"setTimeout“方法，另外，定义一个内部函数，如下所示：
var lights = [
"assets/red.gif",
"assets/yellow.gif",
"assets/green.gif",
"assets/yellow.gif",
];
var index = 0;
function ChangeLights() {
function innerChangeLight(){
index = index + 1;
if (index == lights.length) index = 0;
var image = document.getElementById('traffic');
image.src=lights[index];
}
innerChangeLight();
setTimeout(function () {
innerChangeLight();
}, 1000);
}<!DOCTYPE>
<html>
<body>
<img id="traffic" src="assets/red.gif">
<button type="button" onclick="ChangeLights()">Change Lights</button>
</body>
</html>
Stack Overflow用户
发布于 2017-04-25 02:08:04
试试这个：
var lights = [
"assets/red.gif",
"assets/yellow.gif",
"assets/green.gif",
"assets/yellow.gif",
];
var index = 0;
function ChangeLights(){
setInterval(function() {
if(index == lights.length) {
return;
}
var image = document.getElementById('traffic');
image.src=lights[index];
index = index + 1;
}, 1000);
}<img id="traffic" src="assets/red.gif"><br>
<button onclick="ChangeLights()">Change Lights</button>
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/43594730
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