JavaScript 页面间数据传递的三种实现方案：Cookie、URL 与 LocalStorage

<input id="userName" type="text" />
<input id="passwords" type="password" />
<button id="btn">设置</button>
<button onclick="login()">传递cookie</button>
<button onclick="deletecookie()">删除</button>

//设置cookie
var setCookie = function (name, value, day) {
  //当设置的时间等于0时，不设置expires属性，cookie在浏览器关闭后删除
  var expires = day * 24 * 60 * 60 * 1000;
  var exp = new Date();
  exp.setTime(exp.getTime() + expires);
  document.cookie = name + "=" + value + ";expires=" + exp.toUTCString();
};
//删除cookie
var delCookie = function (name) {
  setCookie(name, ' ', -1);
};
//传递cookie
function login() {
  var name = document.getElementById("userName");
  var pass = document.getElementById("passwords");
  setCookie('userName',name.value,7)
  setCookie('password',pass.value,7);
  location.href = 'b.html'
}
function deletecookie() {
  delCookie('userName',' ',-1)
}

<button onclick="getcookie()">获取</button>

//获取cookie代码
var getCookie = function (name) {
  var arr;
  var reg = new RegExp("(^| )" + name + "=([^;]*)(;|$)");
  if (arr = document.cookie.match(reg)){
    return arr[2];
  }
  else
    return null;
};
//点击获取按钮之后调用的函数
function getcookie() {
  console.log(getCookie("userName"));
  console.log(getCookie("password"))
}

<input type="text" value="猜猜我是谁">
<button onclick="jump()">跳转</button>

function jump() {
  var s = document.getElementsByTagName('input')[0];
  location.href='7.获取参数.html?'+'txt=' + encodeURI(s.value);
}

<div id="box"></div>
var loc = location.href;
var n1 = loc.length;
var n2 = loc.indexOf('=');
var txt = decodeURI(loc.substr(n2+1,n1-n2));
var box = document.getElementById('box');
box.innerHTML = txt;

//将localStorage传递到哪个页面
location.href = 'b.html'
//设置localStorage
window.localStorage.setItem('user','haha');

<button onclick="getcookie()">获取</button>
function getcookie() {
  //获取传递过来的localStorage
  console.log(window.localStorage.getItem('user'))
}