源代码
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>享学课堂</title> </head> <body> <p id="demo"></p> <script> var x = []; document.getElementById("demo").innerHTML = (5 + null) + "<br>" + ("5" + null) + "<br>" + ("5" + 2) + "<br>" + ("5" - 2) + "<br>" + ("5" * "2") + "<br>" + ("5" / "2") + "<br>" </script> </body> </html>
运行结果