​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>JavaScript 数字</h1>
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<p>一个常见的错误是期望这个结果是 102030：</p>
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<p id="demo"></p>
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<script>
var x = 10;
var y = 20;
var z = "30";
var result = x + y + z;
document.getElementById("demo").innerHTML = result;
</script>
​
</body>
</html>
​