​x
 
<!DOCTYPE html>
<html>
<body>
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<h1>JavaScript 赋值</h1>
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<h2>逻辑 OR 赋值</h2>
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<h3>||= 运算符</h3>
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<p>如果第一个值为 false，则分配第二个值：</p>
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<p id="demo"></p>
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<script>
let x = undefined;
x ||= 5;
document.getElementById("demo").innerHTML = "x 的值是：" + x;
</script>
​
</body>
</html>
​