<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> <script src="demo/js/jq_3.3.1_mi.js"></script> </head> <body> <h1>欢迎来到javascript的世界</h1> <script> var js='hello javascript'; alert(js); </script> </body> </html>