JavaScript 15 Ajax异步登陆

/**
* Created by KING on 2017/11/28.
*/

var g_xhr_ui;
var g_xhr_login;
var g_id;

$(document).ready(function () {
on_init_userinfo();
});

function createXMLHttpRequest() {
var xhr;
if (window.ActiveXObject) {
xhr = new ActiveXObject("Microsoft.XMLHTTP");
} else if (window.XMLHttpRequest) {
xhr = new XMLHttpRequest();
} else {
xhr = null;
}
return xhr;
}

function on_init_userinfo() {
g_xhr_ui = createXMLHttpRequest();
if (g_xhr_ui) {
g_xhr_ui.onreadystatechange = handleStateChangeInit;
g_xhr_ui.open("GET", "json\\userinfo.json", true);
g_xhr_ui.setRequestHeader("CONTENT-TYPE", "application/x-www-form-urlencoded");
g_xhr_ui.send(null);
}
}

function handleStateChangeInit() {
if (g_xhr_ui.readyState == 4) {
if (g_xhr_ui.status == 200) {
var resText = g_xhr_ui.responseText;
console.log("The server response: " + resText);
var jsonObj = JSON.parse(resText);
var len = jsonObj.length;
console.log("json length : " + len);
var v_table = "<table>" + "<caption>客户信息表</caption>" + "<th>No</th>" + "<th>Company</th>" + "<th>WebSite</th>" + "<th>Email</th>" + "<th class='th-oper'>Oper.</th>";
for (let i = 0; i < len; i++) {
let v_tr =
"<tr>" +
"<td>" + jsonObj[i].cid + "</td>" +
"<td>" + jsonObj[i].cname + "</td>" +
"<td>" + jsonObj[i].csite + "</td>" +
"<td>" + jsonObj[i].cemail + "</td>" +
"<td class='td-oper'>" + "<a href='#'>Edit</a>" + "</td>" +
"</tr>";
v_table += v_tr;
}
v_table += "</table>";
document.getElementById("id-div-userinfo").innerHTML = v_table;
}
}
}

function on_login_click(thisid) {
var param;
var p_id = document.getElementById("id-input-login-id").value;
g_id = p_id;
var p_pwd = document.getElementById("id-input-login-pwd").value;
var md5_pwd = $.md5(p_pwd);
param = "id=" + p_id + "&pwd=" + md5_pwd;
g_xhr_login = createXMLHttpRequest();
if (g_xhr_login) {
g_xhr_login.onreadystatechange = handleStateChangeLogin;
g_xhr_login.open("POST", "login.php", true);
g_xhr_login.setRequestHeader("CONTENT-TYPE", "application/x-www-form-urlencoded");
g_xhr_login.send(param);
}
}

function handleStateChangeLogin() {
var vLoginStatus;
if (g_xhr_login.readyState == 4) {
if (g_xhr_login.status == 200) {
var vLoginStatus = g_xhr_login.responseText;
console.log("The server response: " + vLoginStatus);
if (vLoginStatus == "1") {
document.getElementById("id-div-login").hidden = true;
document.getElementById("id-div-login-ok").hidden = false;
document.getElementById("id-div-login-ok").innerHTML =
"id : " + g_id + "&nbsp;&nbsp;<a href='index.html'>Logout</a>";
document.getElementsByClassName('th-oper')[0].style.visibility = "visible";
let o_td_oper = document.getElementsByClassName('td-oper');
let len = o_td_oper.length;
for (let i = 0; i < len; i++)
o_td_oper[i].style.visibility = "visible";
} else {
document.getElementById("id-div-login").hidden = false;
document.getElementById("id-div-login-ok").hidden = true;
document.getElementById("id-input-login-id").value = "";
document.getElementById("id-input-login-pwd").value = "";
}
}
}
}