下面编写的程序中JavaScript x.style.backgroundColor = x.style.backgroundColor == "yellow" ? "pink" : "yellow";"中的这行代码是什么？
<!DOCTYPE html>
<html>
<body>
<p>In this example, the setInterval() method executes the setColor() function once every 300 milliseconds, which will toggle between two background colors.</p>
<button onclick="stopColor()">Stop Toggling</button>
<script>
var myVar = setInterval(function(){ setColor() }, 300);
function setColor() {
var x = document.body;
x.style.backgroundColor = x.style.backgroundColor == "yellow" ? "pink" : "yellow";
}
function stopColor() {
clearInterval(myVar);
}
</script>
</body>
</html>
答案 0 :(得分：3)
条件？ expr1：expr2
与以下内容相同：
if (condition) expr1;
else expr2;
所以在你的情况下：
x.style.backgroundColor = x.style.backgroundColor == "yellow" ? "pink" : "yellow"
相当于：
if (x.style.backgroundColor == "yellow")
x.style.backgroundColor = "pink";
else x.style.backgroundColor = "yellow";