let obj={
        name:'jack',
        age:18,
        sex:'girl'
    }
    let obj2={
        name:'rose',
        age:18,
        sex:'boy'
    }
   
    var str={}
    for(let key in obj){
        for(let keys in obj2){
            if(obj[key]!=obj2[key]){
                str[key]=obj2[key]                   
            }
        }
    }
    console.log(str) //{name: "rose", sex: "boy"}
 

兩個對象key相同但是value不同,將value不同的鍵值對以對象形式輸出