javascript - Help, how can I click a button on the page to place a takeout order like this? Beg on your knees!-PHP Tutorial-php.cn

Home

Backend Development

PHP Tutorial

javascript - Help, how can I click a button on the page to place a takeout order like this? Beg on your knees!

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

Jul 06, 2016 pm 01:52 PM

csshtmlhtml5javascriptphp

For example, if a json object contains this information, how can I print it out in such a wide strip?
javascript - Help, how can I click a button on the page to place a takeout order like this? Beg on your knees!

What I want is to print out a small strip of the order information placed by the user. I found that the jquery.jqprint-0.3.js plug-in can be used. It can be called directly with a button. The problem now is that the default width is too large, which is scary. Dead people, I don’t know how to solve them

Reply content:

The poster can go to Taobao to search for gprs printers. Many stores outside have them. It is actually a server-side php push. Some output an xml file. You only need to convert json to xml. Of course, different printers require it. The formats are different. If you are interested in buying one, the boss will definitely provide customer service and technical guidance.

It is unlikely to be implemented on a pure web page.
You need to design hardware communication, that is, calling a special terminal to print receipts. Generally, programmable terminals will provide such SDK. Of course, this may require technical support from the other party.

Usually, this interaction with the hardware is handled through a computer application, also known as a client program.

To provide several ideas, let me explain first that I just thought about it myself and have not implemented it in detail.

1. Implemented through a browser plug-in (in this case, the same device, that is, you click on it yourself, and your current computer is connected to the terminal to print the receipt).
2. Send a general http or socket request to the server through the browser button, and the server connects to the printing terminal (this is not necessarily directly connected to the printing terminal. If so, the printing terminal is usually required to have networking capabilities. Usually, is another computer connected to the terminal for printing). This situation supports that the user clicks the button operation without having to operate it himself, that is, the "button" can be anywhere.

In fact, it is to solve the problem of communication and message delivery. The browser currently does not support direct dealing with hardware, and can only transmit messages through the network.

No peripherals are needed, that is, pure web page output content, connected to the printer for printing.

Format your data on a blank page, then call window.print() to select the paper size.

Thank you for the invitation
Recommend a very useful tool to the poster http://www.lodop.net/
JS operation printer, I hope it can help the poster

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

What are some common problems that can cause PHP sessions to fail?Apr 25, 2025 am 12:16 AM

Reasons for PHPSession failure include configuration errors, cookie issues, and session expiration. 1. Configuration error: Check and set the correct session.save_path. 2.Cookie problem: Make sure the cookie is set correctly. 3.Session expires: Adjust session.gc_maxlifetime value to extend session time.

How do you debug session-related issues in PHP?Apr 25, 2025 am 12:12 AM

Methods to debug session problems in PHP include: 1. Check whether the session is started correctly; 2. Verify the delivery of the session ID; 3. Check the storage and reading of session data; 4. Check the server configuration. By outputting session ID and data, viewing session file content, etc., you can effectively diagnose and solve session-related problems.

What happens if session_start() is called multiple times?Apr 25, 2025 am 12:06 AM

Multiple calls to session_start() will result in warning messages and possible data overwrites. 1) PHP will issue a warning, prompting that the session has been started. 2) It may cause unexpected overwriting of session data. 3) Use session_status() to check the session status to avoid repeated calls.

How do you configure the session lifetime in PHP?Apr 25, 2025 am 12:05 AM

Configuring the session lifecycle in PHP can be achieved by setting session.gc_maxlifetime and session.cookie_lifetime. 1) session.gc_maxlifetime controls the survival time of server-side session data, 2) session.cookie_lifetime controls the life cycle of client cookies. When set to 0, the cookie expires when the browser is closed.

What are the advantages of using a database to store sessions?Apr 24, 2025 am 12:16 AM

The main advantages of using database storage sessions include persistence, scalability, and security. 1. Persistence: Even if the server restarts, the session data can remain unchanged. 2. Scalability: Applicable to distributed systems, ensuring that session data is synchronized between multiple servers. 3. Security: The database provides encrypted storage to protect sensitive information.

How do you implement custom session handling in PHP?Apr 24, 2025 am 12:16 AM

Implementing custom session processing in PHP can be done by implementing the SessionHandlerInterface interface. The specific steps include: 1) Creating a class that implements SessionHandlerInterface, such as CustomSessionHandler; 2) Rewriting methods in the interface (such as open, close, read, write, destroy, gc) to define the life cycle and storage method of session data; 3) Register a custom session processor in a PHP script and start the session. This allows data to be stored in media such as MySQL and Redis to improve performance, security and scalability.

What is a session ID?Apr 24, 2025 am 12:13 AM

SessionID is a mechanism used in web applications to track user session status. 1. It is a randomly generated string used to maintain user's identity information during multiple interactions between the user and the server. 2. The server generates and sends it to the client through cookies or URL parameters to help identify and associate these requests in multiple requests of the user. 3. Generation usually uses random algorithms to ensure uniqueness and unpredictability. 4. In actual development, in-memory databases such as Redis can be used to store session data to improve performance and security.

How do you handle sessions in a stateless environment (e.g., API)?Apr 24, 2025 am 12:12 AM

Managing sessions in stateless environments such as APIs can be achieved by using JWT or cookies. 1. JWT is suitable for statelessness and scalability, but it is large in size when it comes to big data. 2.Cookies are more traditional and easy to implement, but they need to be configured with caution to ensure security.

See all articles