​x
 
<!DOCTYPE html>
<html>
<body>
​
<h1>JavaScript 数字</h1>
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<p>超大或超小数可以用科学（指数）记数法书写：</p>
​
<p id="demo"></p>
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<script>
let x = 123e5;
let y = 123e-5;
document.getElementById("demo").innerHTML = x + "<br>" + y;
</script>
​
</body>
</html>
​