阅读:6276 次 编辑日期:2013-12-16
var str = {fname:"uw3c",lname:"js",age:10} alert(str.fname);//uw3c alert(str.sex);//undefined
var str = {fname:"uw3c",lname:"js",age:10} alert('fname' in str);//true alert('sex' in str);//false