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