<!DOCTYPE html>
<html>
<body>
<h1>JavaScript Task 3- Traffic Light Sequence </h1>
<img id="light" src="./assets/red.png" height="205" width="95">
<button type="button" onclick="changeLights()">Change Lights</button>
<script>
var colours = ["./assets/red.png","./assets/red_and_amber.png", "./assets/green.png","./assets/amber.png" ];
var index = 0;
function changeLights() {
index = index + 1;
if (index == colours.length)
index = 0;
var image = document.getElementById('light');
image.src = colours[index];
}
</script>
</body>
</html>
this code is to show a traffic light sequence. First red, then red and amber, then green, then back to amber, and then back to red. I'm unsure of what the function exactly does line by line.
最佳答案
索引是与颜色数组一起使用的数字。
例如:colours[0] 是数组中的第一个颜色；
然后索引+=1，现在索引==1；
第二次:
colors[1] 是第二个，依此类推
关于javascript - 有人可以解释一下这个函数吗，因为我不确定使用索引的目的，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/40818947/