<!DOCTYPE html> <html> <head> <metacharset="UTF-8"> <title></title> </head> <body> <script> var a = 12; var b = 90; var json = {a:12,b:90,v:978};//存数据的 //json没有length,全部显示 //显示为字符串 alert(json.a); //json的循环 for(var i in json){ alert(i+'是'+json[i]); } </script> </body> </html>