<!DOCTYPE html> <html> <body> <h1>JavaScript 赋值</h1> <h2>减法赋值</h2> <h3>-= 运算符</h3> <p id="demo"></p> <script> let x = 10; x -= 5; document.getElementById("demo").innerHTML = "x 的值是:" + x; </script> </body> </html>