PHP+Ajax verification code to verify user login_php example
One advantage of using AJAX to verify user login is that the jump page does not need to be refreshed. In addition, it is safer to use the verification code, so I wrote it down after a while. A total of three files are used:
yz.php: Generate the PHP file of the verification code. The verification code will be in the SESSION for comparison and calling when logging in
index.php: HTML file for user login
loginCheck.php: File to verify user login
The following is an analysis one by one:
yz.php file
<?php
session_start();
//生成验证码图
Header("Content-type: image/PNG");
//长与宽
$im = imagecreate(44,18);
// 设置背景色:
$back = ImageColorAllocate($im, 245,245,245);
// 填充背景色:
imagefill($im,0,0,$back);
srand((double)microtime()*1000000);
$vcodes;
//生成4位数字
for($i=0;$i<4;$i++){
$font = ImageColorAllocate($im, rand(100,255),rand(0,100),rand(100,255));
$authnum=rand(1,9);
$vcodes.=$authnum;
imagestring($im, 5, 2+$i*10, 1, $authnum, $font);
}
//加入干扰象素
for($i=0;$i<100;$i++){
$randcolor = ImageColorallocate($im,rand(0,255),rand(0,255),rand(0,255));
imagesetpixel($im, rand()%70 , rand()%30 , $randcolor);
}
ImagePNG($im);
ImageDestroy($im);
// 将四位的验证码保存在 SESSION 里，登录时调用对比
$_SESSION["VCODE"]=$vcodes;
?>
index.php: Note, do not take $_SESSION["VCODE"] in this file, otherwise it will be taken one step later, and the previous verification code will be displayed after refreshing
Just verify in loginCheck.php
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
<title>管理后台| 请登录</title>
<link rel="stylesheet" type="text/css" href="\css\a.css">
<style type="text/css">
<!--
#main{
font-family:宋体;
font-size:10pt;
text-align:center;
margin-top:510px;
}
body{
background-attachment:fixed;
background-position:center;
background-image:url(./images/w2.jpg);
background-repeat: no-repeat;
}
#authCode{background-Color:#F8F9FF;}
table{text-align:center;}
//-->
</style>
<script type="text/javascript" src="./js/trim.js"></script>
<script type="text/javascript">
<!--
function clearX(){
document.getElementById('authCode').value="";
}
// 点击图片重新获得新的验证码：
function getVCode() {
var vcode=document.getElementById('vcode');
vcode.src ='yz.php?nocache='+new Date().getTime();
}
//定义XMLHttpRequest对象
var xmlHttp;
// 创建 XMLHttpRequest:
function createXmlHttpRequest(){
var xmlHttp=null;
try{
// Firefox, Opera 8.0+, Safari
xmlHttp=new XMLHttpRequest();
}catch(e){
// Internet Explorer
try{
xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
}catch(e){
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}
}
return xmlHttp;
}
// AJAX 检查登录: 有密码，要用POST 提交
function login(){
var authCode=trim(document.getElementById('authCode').value);
var username=trim(document.getElementById('username').value);
var password=trim(document.getElementById('password').value);
if(username=="" || password=="" || authCode==""){
alert("请输入用户名和密码和验证码！");
return false;
}else{
if(!xmlHttp) xmlHttp=createXmlHttpRequest();
var send_string="username="+username+"&password="+password+"&authCode="+authCode+"&fresh="+Math.random();
xmlHttp.open("POST","loginCheck.php",true);
xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
xmlHttp.send(send_string);
xmlHttp.onreadystatechange=function(){
if(xmlHttp.readystate==4 && xmlHttp.status==200){
var answer=xmlHttp.responseText;
if(answer=="ok") //跳转到管理中心页面
window.location.href="adminCenter.php";
else{
alert("用户名密码或验证码不正确! 请重新输入!");
document.getElementById('username').focus();
}
}
}
}
}
//-->
</script>
</head>
<body onload="document.getElementById('username').focus();">
<div id="main">
<table>
<tr>
<td>用户名:<input type="text" id="username" /></td>
<td>密 码:<input type="password" id="password" /></td>
<td>验证码:<input type="text" id="authCode" size="6" maxlength="4" value="验证码" onfocus="clearX()"/></td>
<td><img id="vcode" src="yz.php" alt="看不清？点击换一张" onclick="getVCode()" /></td>
<td><input id="loginButton" type="submit" value="登 录" onclick="login()"/></td>
</tr>
</table>
</div>
</body>
</html>
loginCheck.php File to verify user login
<?php
session_start();
include("../conn/connDB.php");
// 取得POST过来的参数:
$username=$_POST["username"];
$password=md5($_POST["password"]);
$authCode=$_POST["authCode"];
$feedback="no";
//对比是否==SESSION中的验证码，不能放在客户端做，否则取不正确的值
if($authCode==$_SESSION["VCODE"]){
$SQL="select * from users where username='$username' and password='$password'";
$result=mysql_query($SQL);
$rows=mysql_num_rows($result);
if($rows==1) // 验证成功
$feedback="ok";
$_SESSION["admin"]=true; //为了后台安全，存入SESSION，表明 ADMIN 已登录，供后面调用
}
echo $feedback;
?>
The above is the entire content of this article. I hope it will be helpful to everyone’s study. I also hope that everyone will support Script Home.
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1666
14
1425
52
1327
25
1273
29
1252
24
Explain secure password hashing in PHP (e.g., password_hash, password_verify). Why not use MD5 or SHA1?
Apr 17, 2025 am 12:06 AM
In PHP, password_hash and password_verify functions should be used to implement secure password hashing, and MD5 or SHA1 should not be used. 1) password_hash generates a hash containing salt values to enhance security. 2) Password_verify verify password and ensure security by comparing hash values. 3) MD5 and SHA1 are vulnerable and lack salt values, and are not suitable for modern password security.
PHP and Python: Comparing Two Popular Programming Languages
Apr 14, 2025 am 12:13 AM
PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.
PHP in Action: Real-World Examples and Applications
Apr 14, 2025 am 12:19 AM
PHP is widely used in e-commerce, content management systems and API development. 1) E-commerce: used for shopping cart function and payment processing. 2) Content management system: used for dynamic content generation and user management. 3) API development: used for RESTful API development and API security. Through performance optimization and best practices, the efficiency and maintainability of PHP applications are improved.
PHP: A Key Language for Web Development
Apr 13, 2025 am 12:08 AM
PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7
How does PHP type hinting work, including scalar types, return types, union types, and nullable types?
Apr 17, 2025 am 12:25 AM
PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.
The Enduring Relevance of PHP: Is It Still Alive?
Apr 14, 2025 am 12:12 AM
PHP is still dynamic and still occupies an important position in the field of modern programming. 1) PHP's simplicity and powerful community support make it widely used in web development; 2) Its flexibility and stability make it outstanding in handling web forms, database operations and file processing; 3) PHP is constantly evolving and optimizing, suitable for beginners and experienced developers.
PHP and Python: Code Examples and Comparison
Apr 15, 2025 am 12:07 AM
PHP and Python have their own advantages and disadvantages, and the choice depends on project needs and personal preferences. 1.PHP is suitable for rapid development and maintenance of large-scale web applications. 2. Python dominates the field of data science and machine learning.
PHP vs. Other Languages: A Comparison
Apr 13, 2025 am 12:19 AM
PHP is suitable for web development, especially in rapid development and processing dynamic content, but is not good at data science and enterprise-level applications. Compared with Python, PHP has more advantages in web development, but is not as good as Python in the field of data science; compared with Java, PHP performs worse in enterprise-level applications, but is more flexible in web development; compared with JavaScript, PHP is more concise in back-end development, but is not as good as JavaScript in front-end development.
