<!--pages/login/login.wxml-->
<view class="container">
  <form bindsubmit="formSubmit">
    <view class="row">
      <text>姓 名：</text>
      <input type="text" name="userName" placeholder="请输入用户名" />
    </view>
    <view class="row">
      <text>密 码：</text>
      <input type="password" name="userPassword" placeholder="请输入密码" />
    </view>
    <view class="row">
      <button type="primary" form-type="submit">登陆</button>
    </view>

  </form>
</view>

/* pages/login/login.wxss */
.container{
  padding: 1rem;
  font-size: 0.9rem;
  line-height: 1.5rem;
  border-shadow: 1px 1px #0099CC;
}
.row{
  display: flex;
  align-items: center;
  margin-bottom: 0.8rem;
}
.row text{
  flex-grow: 1;
  text-align: right;
}
.row input{
  font-size: 0.7rem;
  color: #ccc;
  flex-grow: 3;
  border: 1px solid #0099CC;
  display: inline-block;
  border-radius: 0.3rem;
  box-shadow: 0 0 0.15rem #aaa;
  padding: 0.3rem;
}
.row button{
  padding: 0 2rem;
}

// pages/login/login.js
Page({
 data:{
  userName:'',
  userPassword:'',
 },

 formSubmit:function(e){
  console.log(e.detail.value);//格式 Object {userName: "user", userPassword: "password"}

  //获得表单数据
  var objData = e.detail.value;

  if(objData.userName && objData.userPassword){
   // 同步方式存储表单数据
   wx.setStorageSync('userName', objData.userName);
   wx.setStorageSync('userPassword', objData.userPassword);

   //跳转到成功页面
   wx.navigateTo({
    url: '../index/index'
   })
  }
 },

 //加载完后，处理事件 
 // 如果有本地数据，则直接显示
 onLoad:function(options){
  //获取本地数据
  var userName = wx.getStorageSync('userName');
  var userPassword = wx.getStorageSync('userPassword');

  console.log(userName);
  console.log(userPassword);
  if(userName){
   this.setData({userName: userName});
  }
  if(userPassword){
   this.setData({userPassword: userPassword});
  }

 },
 onReady:function(){
  // 页面渲染完成
 },
 onShow:function(){
  // 页面显示
 },
 onHide:function(){
  // 页面隐藏
 },
 onUnload:function(){
  // 页面关闭
 }
})

 <view class="row">
      <text>姓 名：</text>
      <input type="text" name="userName" placeholder="请输入用户名" value="{{userName}}" />
    </view>
    <view class="row">
      <text>密 码：</text>
      <input type="password" name="userPassword" placeholder="请输入密码" value="{{userPassword}}" />
    </view>

// pages/login/login.js
Page({
 data:{
  userName:'',
  userPassword:'',
 },

 formSubmit:function(e){
  console.log(e.detail.value);//格式 Object {userName: "user", userPassword: "password"}

  //获得表单数据
  var objData = e.detail.value;

  if(objData.userName && objData.userPassword){
   // 同步方式存储表单数据
   wx.setStorage({
    key:'userName', 
    data:objData.userName
   });
   wx.setStorage({
    key:'userPassword', 
    data:objData.userPassword
   });

   //跳转到成功页面
   wx.navigateTo({
    url: '../index/index'
   })
  }
 },

 //加载完后，处理事件 
 // 如果有本地数据，则直接显示
 onLoad:function(options){
  var that = this;
  //获取本地数据
  wx.getStorage({
   key: 'userName',
   success: function(res){
    console.log(res.data);
    that.setData({userName: res.data});
   }
  });
  wx.getStorage({
   key: 'userPassword',
   success: function(res){
    console.log(res.data);
    that.setData({userPassword: res.data});
   }
  });
 },
 onReady:function(){
  // 页面渲染完成
 },
 onShow:function(){
  // 页面显示
 },
 onHide:function(){
  // 页面隐藏
 },
 onUnload:function(){
  // 页面关闭
 }
})