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HomeBackend DevelopmentPHP TutorialFirst introduction to PHP, first introduction to educational technology_PHP tutorial

First introduction to PHP, first introduction to educational technology

1. In PHP, global variables must be capitalized;

2. In the PHP form submission method, the method attribute sets the method of obtaining and submitting data;

3. If the upload element is used in the form, then add attributes to the form: enctype="multipart/form-data";

4. Implementation of user logout function:

Copy code The code is as follows:

session_start(); //Start session
​​​ unset($_SESSION['user']); //Delete a single session
​​  unset($_SESSION['pwd']); ​ //Delete a single session
session_destory(); //End the current reply
       header("location:index.php"); //Redirect
?>

Delete multiple sessions: $_SESSION=array();

Traversing objects in 5.php:

Copy code The code is as follows:

for($i=0;$i //Processing
}

6.php contains files: include("file path");

7. How to embed js script in HTML page:

Copy code The code is as follows:


8. Reference JS files in php dynamic pages:

Copy code The code is as follows:


Or:

9. Solve the problem that the browser does not support JavaScript:
a. Enable JavaScript support in IE browser;
b. Enable IE browser’s support for local JavaScript;
c. Use comment symbols to verify whether the browser supports JavaScript script function;
d. Use the tag to verify whether the browser supports JavaScript scripts.

10. In php, the processing mechanisms of single quotes and double quotes are different. Their differences:
The contents of double quotes can be interpreted and replaced, while the contents of single quotes are treated as ordinary characters. Such as:

Copy code The code is as follows:

$test="PHP";
        $str1="I like $test";
$str2='I like $test';
echo $str; //Output: I like PHP;
echo $str; //Output: I like $test;
?>

I am new to PHP and don’t know much about user registration and login. I hope you guys can give me some advice... (it’s best to have an example) haha

condb.php
$con = mysql_connect("localhost","root","123456");
if (!$con) {
die("Query is failed :" . mysql_error());
}
mysql_select_db("login_schema");

mysql_query("set names 'utf8'");
?>
login.php
session_start();
if (isset($_SESSION['errorMsg']) && $_SESSION['errorStatic'] == 1){
echo "" . $_SESSION['errorMsg'] . "";
}else{
unset($_SESSION['errorStatic']);
}
?>
















User Login
username  : 
password  : 
>
 

php调用数据库问题

主页面




传值页面get_Dir.php
header("Content-Type:text/html; charset=gb2312");
//echo "POST:".$_POST['id'];
$SClassID=$_POST['id'];
$conn=mysql_connect("localhost","root","");
mysql_select_db("数据库名");
mysql_query("set names 'gb2312'");
$query=mysql_query("select * from 表名 where id='$SClassID'");
while($row=mysql_fetch_array($query)){
echo ">
 

www.bkjia.comtruehttp://www.bkjia.com/PHPjc/886147.htmlTechArticle初识PHP,初识教育技术 1.在PHP中,全局变量都要大写; 2.在PHP表单提交方式中,method属性设置了获取和提交数据的方式; 3.如果在表单中使...
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How can you check if a PHP session has already started?How can you check if a PHP session has already started?Apr 30, 2025 am 12:20 AM

In PHP, you can use session_status() or session_id() to check whether the session has started. 1) Use the session_status() function. If PHP_SESSION_ACTIVE is returned, the session has been started. 2) Use the session_id() function, if a non-empty string is returned, the session has been started. Both methods can effectively check the session state, and choosing which method to use depends on the PHP version and personal preferences.

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Sessionsarevitalinwebapplications,especiallyfore-commerceplatforms.Theymaintainuserdataacrossrequests,crucialforshoppingcarts,authentication,andpersonalization.InFlask,sessionscanbeimplementedusingsimplecodetomanageuserloginsanddatapersistence.

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Managing concurrent session access in PHP can be done by the following methods: 1. Use the database to store session data, 2. Use Redis or Memcached, 3. Implement a session locking strategy. These methods help ensure data consistency and improve concurrency performance.

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PHPsessionshaveseverallimitations:1)Storageconstraintscanleadtoperformanceissues;2)Securityvulnerabilitieslikesessionfixationattacksexist;3)Scalabilityischallengingduetoserver-specificstorage;4)Sessionexpirationmanagementcanbeproblematic;5)Datapersis

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Load balancing affects session management, but can be resolved with session replication, session stickiness, and centralized session storage. 1. Session Replication Copy session data between servers. 2. Session stickiness directs user requests to the same server. 3. Centralized session storage uses independent servers such as Redis to store session data to ensure data sharing.

Explain the concept of session locking.Explain the concept of session locking.Apr 29, 2025 am 12:39 AM

Sessionlockingisatechniqueusedtoensureauser'ssessionremainsexclusivetooneuseratatime.Itiscrucialforpreventingdatacorruptionandsecuritybreachesinmulti-userapplications.Sessionlockingisimplementedusingserver-sidelockingmechanisms,suchasReentrantLockinJ

Are there any alternatives to PHP sessions?Are there any alternatives to PHP sessions?Apr 29, 2025 am 12:36 AM

Alternatives to PHP sessions include Cookies, Token-based Authentication, Database-based Sessions, and Redis/Memcached. 1.Cookies manage sessions by storing data on the client, which is simple but low in security. 2.Token-based Authentication uses tokens to verify users, which is highly secure but requires additional logic. 3.Database-basedSessions stores data in the database, which has good scalability but may affect performance. 4. Redis/Memcached uses distributed cache to improve performance and scalability, but requires additional matching

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Sessionhijacking refers to an attacker impersonating a user by obtaining the user's sessionID. Prevention methods include: 1) encrypting communication using HTTPS; 2) verifying the source of the sessionID; 3) using a secure sessionID generation algorithm; 4) regularly updating the sessionID.

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