1 <!DOCTYPE HTML> 2 <html> 3 <head> 4 <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 5 <title>无标题文档</title> 6 </head> 7 8 <body> 9 <script> 10 function a(){ 11 return 1; 12 } 13 14 alert(a()); 15 </script> 16 </body> 17 </html>
函数先定义，再调用，调用之后要给返回值