将列表添加到localstorage中的列表数组

Question

从用户输入表格中我有以下表格的学生列表:

 //student form input for 1st time
 var student={name:"a",roll:"9",age:13}
 //student form input for 2nd time
 var student={name:"b",roll:"10",age:14}
 //student form input for 3rd time
 var student={name:"c",roll:"11",age:15}

实际上,我正在开发phonegap应用程序.每次用户提交表单输入即学生信息时,我都希望将它们保存到本地存储中.最后,在线时,我想同步它们.我知道我可以将它们存储在本地存储中,如下所示:

 localStorage.setItem("studentinfo", JSON.Stringfy(student));

但是,当我保存第二个学生信息时,这将删除本地存储中的第一个学生信息.

事实上,当我分别保存第一个,第二个和第三个输入时,我想将它们添加到localstorage数组中,最后localstorage中的结果应该像

key=studentlist,
value=[
       {name:"a",roll:"9",age:13},  
       {name:"b",roll:"10",age:14},
       {name:"c",roll:"11",age:15}
    ]

如何在localstorage或phonegap localstorage中完成？

Answer 1

您希望将所有学生都安排在这样的数组中:

var students = [];
students.push({name:"a",roll:"9",age:13});
students.push({name:"b",roll:"10",age:14});
students.push({name:"c",roll:"11",age:15});

然后将其存储在localStorage:

localStorage.setItem('studentsInfo', JSON.stringify(students));

最好的方法是使用这样的函数:

// When you get more student information, you should:
var addNewStudent = function (name, roll, age) {
    // retrieve it (Or create a blank array if there isn't any info saved yet),
    var students = JSON.parse(localStorage.getItem('studentsInfo') || [];
    // add to it,
    students.push({name: name, roll: roll, age: age});
    // then put it back.
    localStorage.setItem('studentsInfo', JSON.stringify(students));
}