前言：今天写了个小练习，把这几天看的东西巩固一下，在这个程序中用到了localStorage存储和json串的转换。
下面是具体的实现代码：
（1）首先判断是否存在用户，从而显示相应的界面
function isUser()
{
var storage = window.localStorage;
if (storage.user != undefined)
{
document.getElementById("showmess").style.display = "block";
document.getElementById("fillmess").style.display = "none";
}
else
{
document.getElementById("showmess").style.display = "none";
document.getElementById("fillmess").style.display = "block";
}
}
（2）存储用户信息
var pic; //全局变量存储图片信息
/*从本地电脑获得图片*/
function add_files(files) {
if (files.length) {
var file = files[0];
var reader = new FileReader();
reader.onload = function(e) {
document.getElementById("userpic").src = e.target.result;
pic = e.target.result;
}
reader.readAsDataURL(file);
}
}
function saveUserMess()
{
var name = document.getElementById("username").value;
if (name != "")
{
var storage = window.localStorage;
var jsonObj = {
name:name,
icon:pic
};
var user = JSON.stringify(jsonObj);
storage.setItem("user",user);
}
else
{
alert("昵称不为空");
}
}
（3）用户输入便签内容，并保存
function save_diary()
{
var headle = document.getElementById("headle").value;
var cont = document.getElementById("diary").value;
if (headle != "" && cont != "")
{
var storage = window.localStorage;
if (storage.diary != undefined)
{
var diary = storage.getItem("diary");
var jsonObj = JSON.parse(diary);
var diaryItem = {
headle:headle,
diary:cont,
date:new Date()
};
jsonObj.push(diaryItem);
var data = JSON.stringify(jsonObj);
storage.setItem("diary",data);
}
else
{
var jsonObj = [{
headle:headle,
diary:cont,
date:new Date()
}];
var diary = JSON.stringify(jsonObj);
storage.setItem("diary",diary);
}
}
else
{
alert("标题和内容不为空哦");
}
}
（4）将用户便签信息显示在见面
function showDiary()
{
var storage = window.localStorage;
var mess = JSON.parse(storage.user);
if (storage.diary != undefined)
{
var json = JSON.parse(storage.diary);
var div_id = document.getElementById("diarymess");
for (var i = 0; i < json.length; i++)
{
div_id.innerHTML+='<div><button class="btn btn-success"'+'type="button" id="dropdownMenu" onclick="show(this)"><div class="col-md-4"><img src='+mess.icon+' class="img-circle size" id="userpic"><br><font style="text-align:center">'+mess.name+'</font></div><div class="col-md-8"><h2>'+json[i].headle+'</h2><font>'+json[i].date+'</font></div><span class="caret" style="margin-top:50px;">'+'</span></button><p style="display:none">'+json[i].diary+'</p><div>';
}
}
}
