Php website problemsроботи

Для нашого онлайн магазину шукаємо PHP розробника фрілансера Маємо два цікаві проекти. Завдання: Шукамо фрілансера для розвитку наших веб-магазинів електронної комерції за допомогою найсучасніших веб-технологій для різних пристроїв (мобільних, планшетів) Профіль: • Хороші знання з програмного забезпечення (об'єктно-орієнтований дизайн, шаблони проектування, тестування) • самостійна робота та вирішення проблем • високий рівень мотивації • Досвід роботи з PHP, Symfony, Laravel або Zend, є перевагою • Вільне володіння німецькою чи англійською мовами • Дуже хороші знання PHP, MySQL та JavaScript • Добре знання HTML (5) та CSS (3)

Потрібно поступово (по частинах) переписати застарівший самописний PHP інтернет-магазин з асортиментом декілька тисяч товарів на фреймворк Django, розширюючи його теперішній функціонал. Обов'язково: - попередній досвід веб-розробки на Django; - досвід створення RESTful API; - розуміння PHP. Бажано: - досвід на подібних проектах в ролі Senior; - досвід роботи з Flask; - досвід роботи з Vue.js; - досвід роботи з PostgreSQL.

needs to be finalized - add btc, payeer, perfect money, yandex money, visa / mastercard, pay pal payment methods. And also to add the calculator of interest calculation concerning the purchased investment packages by the client (so that the client can see the purchased package and accruing on it depending on the elapsed time and for the current period after payment in his own office). Change the site's payment currency to dollars, euros, rubles, pounds. The project budget is 50 Euros, but we can discuss.

Рекламна агенція Афіша Прикарпаття шукає PHP-програміста для виправлення технічних помилок на сайті ap.if.ua. Сайт написано за допомогою фреймворку Laravel, попередній програміст пояснить всі технічні деталі. Приблизна вартість всіх виправлень на сайті - 10000 грн. Можливо будуть добавлятись нові пункти, за додаткову оплату. Якщо працювати 5 днів в тиждень то все можна закінчити приблизно за пару тижнів, залежить від ваших навичок. Нам потрібна тільки людина з Івано-Франківська(та області) для того, щоб ми могли зустрічатись в офісі Афіша Прикарпаття, також при необхідності можливе виділення робочого місця.

Доброго дня. Я партнер міжнародної IT-компанії, яка займається розробкою додатків та сайтів (від звичайних лендінгів до повноцінних адмін-сторінок) для американського ринку. Ми шукаємо працьовитих і готових до навантаження PHP девелоперів. У команді мало людей, тож усі мають достатньо роботи і справді дружні між собою. Майже усі наші працівники з України, тож проблем з комунікацією немає. Більшість контактів будуть здійснюватись через менеджерів компанії та мене, тож безпосередній контакт з клієнтами англійською буде відсутній. Однак володіння англійською хоча б на простому розмовному рівні потрібне, оскільки мій парнер по бізнесу - американець, і комунікація з ним у вас буде. Розпочати роботу ви зможете після кількох етапів відбору (тест на навики та коротка скайп-розмова) та р...

Я маю довгострокову роботу, яка пов'язана з нашим попереднім проектом 'Change Framework CMS from Shopify to Prestashop - PHP, HTML, CMS, SQL'

I need a proficient PHP developer experienced in manipulating URL accessibility. Ideally, only Google bots should access the URL, keeping the link invisible to all other including real human. The task requires the ability to: - Leverage PHP to restrict access to the specific URL; - Use user agent string detection to discern between Google bots and real human users; - Block all real users, regardless of their geographical location or device used. Your extensive background dealing with PHP, coupled with a solid understanding of user agent strings, is essential for this project. If you have previous experience working on similar projects, those will be advantageous. Please share examples of your past work if possible.

I need an experienced developer who can identify and fix the error messages my ASP.NET Web API is sending. Key Points: - Urgency: This is a critical issue and I need it resolved within a day. - Skills: You should have a strong background in ASP.NET and be able to quickly diagnose and rectify errors. Your responsibilities: - Investigate the error messages bei...a critical issue and I need it resolved within a day. - Skills: You should have a strong background in ASP.NET and be able to quickly diagnose and rectify errors. Your responsibilities: - Investigate the error messages being produced by my ASP.NET Web API. - Resolve any issues that are causing these errors. This is an urgent project and I'm looking for someone who can immediately address the problems and provide a qu...

I'm currently experiencing some issues with my website that require a developer experienced in CodeIgniter and PHPMyAdmin to resolve. Additionally, I require some new functions to be added to my website's admin panel. Key Areas of Work: - Fixing Error Messages: The site is currently displaying error messages related to database connections and functionality. These need to be debugged and resolved. - Adding New Functions: I'm looking to enhance the admin panel with new features in the following areas: - User Management: I need a more robust user management system to be implemented. - Content Management: The content management system should be optimized for smoother operation. - Reporting and Analytics: I require better tools for analytics and reporting within th...

...user experience and the user interface of my website. I recently conducted a performance test on my website, and the results were less than ideal; only scoring 33%. The main problems I've identified include: - Broken links - Page loading issues - Mobile responsiveness problems Additionally, I am looking for a some redesign of the website to provide a better user experience. I would like the following improvements in UX and UI: - Clear and intuitive navigation - Consistent branding and visual identity - Responsive design for mobile devices The target audience for my website is general consumers. Ideal skills and experience for this job include: - Proficiency in WordPress development - Strong background in UX and UI design - Knowledge of ...

I need a skilled PHP developer to create a few pages with a modern and interactive design. The web pages should incorporate functionalities like user registration and login, along with a contact form. This assignment requires a deep understanding of PHP along with a creative mind to ensure a user-friendly design that promotes interaction. Ideal Skills: - PHP development - Web design - Experience developing registration/login processes - Experience creating web-based contact forms

As an online entrepreneur, I'm struggling with the slow loading speed of my WordPress website. This is exacerbated by high server resource usage and poor caching and optimization. More worryingly, I'm dealing with an excessively large Document Object Model (DOM) that further hinders the performance of my site. However, I'm unable to pinpoint specific issues caused by this. I require a skilled professional with in-depth knowledge of WordPress performance optimization to address these problems. The right person should be able to streamline my site for faster loading speed and lower server resource usage. They should also have experience in proper site caching and optimization, and have technical know-how to handle DOM size reduction and enhancements, making the ...

My SIP Trunking system is constantly preventing me from receiving inbound calls. It's a constant issue that requires urgent attention. Ideal candidates will possess: - Extensive experience with SIP Trunking - Knowledge in diagnosing and resolving call reception problems - Proficiency in troubleshooting technical issues constantly, not sporadically.

I need a proficient PHP developer who can help me sign XML files and send them through SOAP using a .p12 certificate from FMNT in Spain. We need to use XMLDSig in the body of the message SOAP using: • Sign Algorith : RSA/DSA (better RSA - ) • Canonicalization: "exc-c14n" (Exclusive) • Digest Algorith : "sha1" ( - The certificate will be used on a web-based platform, which requires a professional with strong experience in working across different web environments. - The primary purpose of this project is to authenticate company data securely ensuring data integrity. - Ideal skills include a strong background in PHP, SOAP, XML, web security, and familiarity with .p12 certificates and FMNT standards

I'm in need of a professional who can help me address a micro cracking issue in the flooring and ceiling of two rooms. The current materials in place are wood, which is susceptible to these problems. Key Deliverables: - Identify and rectify micro cracking in the wood flooring and ceiling of two rooms - Implement solutions to eliminate the sound of micro cracking - Ensure the materials' strength and durability are improved Ideal Skills: - Proficiency in woodwork and floor repair - Experience in addressing micro cracking issues - Understanding of soundproofing techniques The objective is to restore these living spaces to their former glory, removing the annoying sound of micro cracking while enhancing the strength and durability of the materials. A keen eye for detail an...

I need a skilled PHP developer for a project that requires merging multiple images into a single template. The primary task is to overlay images on top of a template, creating a final image that is a combination of all the images. Key requirements include: - Merging multiple images: This project involves overlaying several images on top of each other to create a final composite image. - Positioning and Size: The ability to adjust the positioning and size of the images being overlaid is essential. While I prefer a simple drag and drop tool to adjust these parameters, the output should be precise. - Output Formats: The final image should be available in both JPEG and PNG formats. Ideal skills and experience for this job include: - Strong proficiency in PHP: Since this project...

** FAVOR DE VER Y LEER EL PDF ADJUNTO CUENTA DEMO WEB Se requiere un reporte con la siguiente información: Reporte en donde marca el máximo valor de nivel de combustible (carga) en este caso es 20,000lts El reporte deberá tener la condición para tomar el punto de carga de si se conservo en un nivel alto por más de 10 minutos, no se ha movido y no cambio el valor digamos 5000,10000,15000,20000lts lo marcará como carga, cuando este detenido por 10 minutos y empiece a detectar movimiento de descarga de más de 2000 litros lo tomará como descarga el ultimo valor más grande. • El reporte se debe generar en el mismo sitio en donde se generan actualmente (imagen 1) Se requiere el formato PDF, HTML y XLS como los de Fuel fil...

...project and urgently require skilled assistance. The primary problems include persistent build errors and several UI layout issues. Ideally, the chosen candidate will be proficient in working with the Flutter framework, experienced in solving similar issues, and familiar with both Android and iOS development. • Build Errors: My project has been spawning various build errors that hinder the execution of the application. The freelancer is expected to help identify and rectify these errors. • UI Layout Problems: There are also vital concerns with the user interface layout. Some pages don't render correctly on different screen sizes, and the general responsiveness of the UI is inconsistent. The task would involve pinpointing these problems and implemen...

Hi, I am a python programmer and I am trying to learn how to code with the OpenHoldem framework, but since I have very little knowledge of C++, I feel a bit overwhelmed by the huge documentation, for this reason I am searching for someone with experience with OpenHoldem, and who already knows how to play poker to be able to understand what I want my bot to do, and transcribe it...on the opponents (I will provide with a list of players against whom it has to change some choices in game) -it needs to base its choices on a few specific decisional processes that I will tell you, but they won t be complex, it will all be pretty straightforward Obviously I will tell you exactly what I need the bot to do in advance in further details, in order to avoid misunderstandings and problems durin...

I am currently experiencing design and layout issues with my website, which need expert-level intervention. I require a knowledgeable and meticulous professional to thoroughly evaluate my site, identify the root of these layout problems, and implement feasible solutions to prevent them from recurring. Key Responsibilities: • Identifying and resolving design and layout issues. • Providing post-optimization support to ensure issues do not recur. Desired Skills and Experience: • Proven experience in website design and development. • Strong attention to detail and problem-solving skills. • Expert knowledge of responsive design principles and practices. • Extensive experience with web design tools, languages, and frameworks. Note: Strong ...

Perform an in-depth sensitivity analysis of a Pressure Swing Adsorption (PSA) process for CO2 capture using zeolite 13X. Scale up a CO2 capture system from a small-scale experimental study detailed in the attached research paper to an industrial application focusing on a flue gas stream solely made up of CO2 and N2. This comprehensive investigation can be based on specific equations, data, ...equations from research papers. - Expertise in sensitivity analysis and scale-up projects. - Ability to translate experimental data into practical, large-scale applications. Goals: - Evaluate key metrics such as CO2 recovery%, purity, energy efficiency, and cost in various operational scenarios. I am looking forward to working with somebody who shares a passion for solving complex scientific pro...

I'm experiencing some issues with my file in WooCommerce. I need a skilled developer who can debug and fix these problems.

...trafficking on the dark web? this is how my paper starts A great chance to shine transformed into a living nightmare for one teenage model. Yes, you read that right! We can not even imagine how just one click on any website can share our data on the dark web, something similar happened to a young girl. In the summer of 2017, Chole Ayling a British model living in London was lured into a fake photoshoot in Milan, Italy. After arriving in Milan, she got kidnapped by a group named “The BLACK Death” to be sold as a sex slave on the dark web. This incident emphasizes several major problems, which include the fact that there are groups and people engaged in elaborate online human trafficking operations on the dark side of the internet. and My paper shild be in Mla ...

I'm seeking a skilled Full Stack Developer with extensive experience in PHP to develop a web application. The primary functionalities I'm looking for in this project are around the API and the ability to handle data updates. Key Requirements: - Expertise with PHP: The ideal candidate should have a strong background in PHP, with the capability to develop robust and efficient code. - Full Stack Proficiency: The project requires both frontend and backend development. Proficiency in both areas is crucial for the success of this project. - API Development: You should have experience in developing APIs, especially around data updates. This is a core part of the requirements. The project is focused on developing a web application and ensuring that the API is cap...

...prefer. The old website was on WordPress, but the guy used ACF and created some custom fields for company employees to register stores separated by state and city. There's also something about taxonomy; he created 2 custom post types: 'office' and 'officearea.' In the old WordPress, it worked like this: 1 - User goes to the offices menu, where all states are listed. 2 - User chooses a state, and that state's name is in the URL. 3 - It seems the guy made a PHP script that retrieves the chosen state from the URL, then loops through and displays only the offices in that state. 4 - User clicks on an office and lands on the office's information page. I managed to make this entire structure work on my new WordPress + Divi theme + ACF. I tin...

I'm currently experiencing a syntax error within a data retrieval process in my SOAP database management system. This error is interrupting the smooth functioning of my website and application. Requirements: - Extensive knowledge and experience in PHP and SOAP. - Proven track record of successfully resolving syntax errors, particularly within data retrieval processes. - Ability to identify, debug and promptly solve syntax issues. - Ability to work efficiently, ensuring minimal downtime during fixes. Additionally, recommendations for preventing similar issues in the future would be appreciated. The ideal candidate should be available to start as soon as possible.

I am seeking a proficient Flutter developer to create an application for both iOS and Android platforms, with integral backend development using PHP/MySQL. Key Responsibilities: * Develop a Flutter app for both Android and iOS platforms. * Backend development of the app using PHP/MySQL. * Creation of Data fetching APIs for seamless user-experience. Ideal Skills: * Proficient in Flutter * Extensive experience with PHP/MySQL backend development * Skilled and knowledgeable in creating Data fetching APIs If you have proven experience in similar projects, I am willing to discuss the details further. Your understanding and expertise in Flutter development and API creation is paramount for this project.

... I need someone who has experience in academic writing in this domain (EEG data, Autism, Deep learning). I would like to see his/her some published papers in these or related domains before assigning/awarding this project. After this confirmation, I can share the details of my projects, only including fundamental methodology and comprehensive results. Thus, an expert can easily identify the problems, design the solution based on our method and results, and write an attractive storyline for the entire paper. If the writer needs some new results to complete his story, I would love to add new experiments and results. Therefore, I am looking a person who has experience in above domain. The ultimate goal is to publish this project/work in a high-impact journal. I also have a rich ex...

I'm in need of a talented PHP Nextjs developer for a project involving a range of tasks including Backend development, Frontend development, and API integration. If you're well versed in PHP and JavaScript, and have extensive experience working with , this could be the ideal project for you. Key Tasks: - Backend development: I require a skilled developer to build and maintain the server-side of the web application. - Frontend development: I need assistance with the development and maintenance of the client-side of the application. - API integration: Experience integrating various APIs is a must for this project. Specific Features: - User Authentication: You'll be responsible for implementing a secure and user-friendly authentication system. - Database Integra...

I'm in need of a PowerApp expert to assist with the data input and validation aspects of my project. The data I'm working with is fairly simple, mainly consisting of text and numbers. ( required only technical support ...only technical support online) Key Responsibilities: - Implementing advanced data validation: This includes cross-field validation, custom business rules, pattern matching and range validation. Ideal Skills: - Strong PowerApps development experience. - Proficient understanding of data validation principles. - Ability to craft custom validation rules. - Ability to think creatively and solve problems effectively. This is a challenging project and I need someone with a high level of expertise in PowerApps to ensure the implementation of precise and effect...

...slow website loading times and database slowdowns, which is unacceptable as I regularly have more than 500 concurrent visitors. The primary focus of this project will be optimizing the server's Plesk settings, Postgres and MariaDB databases, and PHP 8.2 configuration. Key tasks will include, but are not limited to: - Configuring Plesk for optimal performance, including adjusting server pool size - Identifying and implementing improvements to Postgres and MariaDB settings to reduce slowdowns - Tuning PHP 8.2 to enhance website speed and performance Ideal candidates for this project will have: - Proven experience in optimizing dedicated servers, particularly with Plesk and Almalinux - A solid understanding of database optimization, including Postgres ...

I'm seeking a skilled PHP/MySQL developer to create a custom PHP POS application. This job will require you to have good experience in PHP/MySQL. You will be paid on a task-based. We will test you with some sample tasks. To be eligible for further discussion I want you to have a look into the portal by visiting the below link and create a free account and try the portal give me one issue you have faced and can be improved in the portal. If you are unable to do above then your application will be rejected immediately.

As an Audi owner, I'm currently seeking a proficient car mechanic who specializes in engine maintenance and repair. The project involves a major repair on my Audi's engine. Essential Skills and Experience: - Specialist knowledge of Audi vehicles - Proven experience in engine repair - Ability to diagnose and solve complex engine problems - Excellent reliability and time management

I'm in urgent need of a full stack PHP developer for a custom web application. The ideal candidate should be proficient in both front-end and back-end development, as well as database management. Key Responsibilities: - Developing a custom web application using PHP - Implementing both front-end and back-end features - Ensuring proper database management Key Requirements: - Prior experience in developing custom web applications - Proficiency in PHP, with a solid background in both front-end and back-end development - Experience with managing databases - Good understanding of security and scalability - Ability to work in a fast-paced environment - Strong problem-solving skills Please note that knowledge of any specific frameworks like Laravel, CodeIgniter, or Sy...

I need a skilled PHP developer with full-stack capabilities for an urgent web application project. The primary purpose of this project is the development of a web application, with a major focus on user login and authentication. Key Tasks: - Front-end Development: The ideal candidate should be proficient in creating user-friendly interfaces that are engaging and responsive. - Back-end Development: A strong understanding of server-side languages and database management is essential for this project. - Database Integration: The successful candidate will be responsible for integrating and managing databases to ensure seamless operation of the web application. The most important feature of this web application is user login and authentication. As such, the developer should have a pro...

I'm in urgent need of a PHP developer to create and implement APIs. The API will be utilized by a frontend that's already been designed. Key Project Details: - I'm looking for APIs to cater to User authentication, Data retrieval, Data manipulation and allow for file uploads. - The project has an 'ASAP' deadline, so I'm seeking a developer who can start immediately and work quickly without compromising quality. Ideal Candidate: - Proficient in PHP and experienced in API development - Skilled in creating secure and efficient user authentication systems - Capable of executing data retrieval, manipulation, and file upload functionalities with precision and speed

*** FAVOR DE VER Y LEER EL PDF ADJUNTO CUENTA DEMO WEB Se requiere un reporte con la siguiente información: Reporte en donde marca el máximo valor de nivel de combustible (carga) en este caso es 20,000lts El reporte deberá tener la condición para tomar el punto de carga de si se conservo en un nivel alto por más de 10 minutos, no se ha movido y no cambio el valor digamos 5000,10000,15000,20000lts lo marcará como carga, cuando este detenido por 10 minutos y empiece a detectar movimiento de descarga de más de 2000 litros lo tomará como descarga el ultimo valor más grande. • El reporte se debe generar en el mismo sitio en donde se generan actualmente (imagen 1) Se requiere el formato PDF, HTML y XLS como los de Fuel ...

I currently have a PHP script that echo's the value of a MySQL db and results appear 3 to a page using Pagination. I'd like the script modified to filter results. There should be a drop down box on the page with the selections of the drop down corresponding to the table column and when selected only the rows with the value of the column appear while still only displaying 3 to a page with page back and forward controls. In the below example of a db table the drop down box would contain the selections 1, 2 and 3. When the used selects 1 then the page output would only display Bob, Jane and Sarah. This is an already existing page with css in the output. Name Address. number ------------------------------------------------------ bob brisbane. ...

As a client, I'm currently experiencing an unspecified "controller not found" bug in my Laravel application. Unfortunately, I haven't been able to determine any exact error messages, affected pages/routes, or recent application changes that could be related to the issue. I'm looking for an experienced Laravel developer wit...Laravel developer with the following skills: - Debugging and troubleshooting Laravel applications - Comprehensive understanding of Laravel controller structures My main goal is to have the current bug fixed efficiently and professionally. Don't hesitate to ask if you have any questions. Please include any similar Laravel bug fixing experiences in your proposal. Your ability to describe the possible problems based on the lack of sp...

php 8.3 downloaded from . I require an expert in PHP installation and testing on my Windows 10 LAPTOP. I do not need Xampp or Wamp.

I'm searching urgently for an experienced PHP architect who can construct a unique e-commerce shopping cart and accompanying admin panel. Key Responsibilities Include: - Constructing a product catalog and search functionality to allow customers to easily browse and locate items. - Integrating an 'Add to cart and checkout' feature ensuring a simple and smooth transaction process. - Developing order management and inventory tracking system within the admin panel to help me keep track of orders and product stocks. Skills and Experience Required: - Proficient in PHP programming - Experience in developing e-commerce websites - Solid understanding of databases and SQL - Familiarity with different payment solutions Although there is no specific requirement fo...

I need a skilled developer to integrate an International Payment Gateway into my PHP-based website immediately. Integration of Payment Getway in the website which will accept USD and this should work in Both Indian people and Other Countries. Website URL is - freelancerbridge(dot)com

I am in need of a professional who can promptly install and customize a PHP script for me. The PHP script I need to be installed is purchased through codecanyon. You will install, test all functions and activate license on our server. Being somewhat urgent, my requested completion for this project is ASAP. I value efficiency and swift, quality work. Thank you

Se requiere un script de RIFAS o SORTEOS con las siguientes opciones: - Escrito en PHP y soporte MYSQL. - Emitir boletos en orden consecutivo (ejemplo 10000 - 999999), el rango de números debe ser personalizable (Ejemplo: 000001 - 999999, 5450 - 54500, etc.) - Poder ingresar el precio de los boletos de la rifa - Capacidad de albergar la rifa de otros usuarios (multi-usuario, multi nivel). - Pagar boletos a través de la opción de tarjeta de crédito de PayPal (con o sin cuenta de PayPal) o por transferencia, modo manual, mostrando información bancaria del propietario ded la rifa. - Ingresar dirección de correo electrónico, Nombres, Apellido, Ciudad, Estado, Número de teléfono de contacto. - Después de recibir el ...

I need a robust StarCloud print feature integrated to my website through PHP. I require an expert in PHP who understands how to efficiently generate receipts directly from a website. Key Features Required: - Personalized receipt printing: Upon a successful order, a receipt should be generated for that specific transaction. - Simplified design: The receipt should be simple, uncluttered and easy to read. Please note, only the code is needed, no additional information like payment or customer details should be included. Ideal skills and experience: - PHP proficiency to ensure seamless integration - Familiarity with StarCloud system - Understanding of efficient coding practices for smooth running.

I'm in need of a skilled PHP CodeIgniter Developer to help me debug my existing application. Key Points: - The main goal of this project is to fix bugs within the current application. Therefore, I require someone with a strong background in troubleshooting and debugging. - I'm specifically looking for a developer with extensive experience in PHP CodeIgniter. Therefore, please highlight your experience in this specific framework when you apply. Ideal Candidate: - Proficient in PHP CodeIgniter - Proven experience in debugging applications - Strong problem-solving skills - Excellent attention to detail - Ability to work independently and efficiently Please make sure to include your experience in your proposal. Looking forward to working together.

I am seeking an expert in AWS servers, particularly in the problem-solving aspect of EC2 instances. Key tasks to be performed: - Diagnose the specific issues of the server - Suggest and implement suitable solutions to rectify the problems - Maintain and improve server performance Ideal Expertise and Skills: - Strong technical skills and deep understanding of AWS, specifically EC2 instances - Proven track record in handling server emergencies and solving server issues - Competence in developing and maintaining customer-focused, high-performance AWS infrastructure - Proficient with best practices in ensuring server security

Good evening, I need help with a Python assignment and I also need programming tutorials in java, Python, mvc, php, Javascript, mysql, jQuery, html, css, asp.net, c#. The tutorials would be in Spanish. I need them as soon as possible.

I'm in need of someone adept at PHP and SOAP. My development site is currently returning a warning message: "Attempt to read property "Invoice_Number" on string." I've set up a dev SOAP server for you to carry out the work. At this point, I'm uncertain if I'm attempting to access the "Invoice_Number" property on a string. There are also no other error messages accompanying this issue. Key tasks: - Identify the cause of the "Invoice_Number" warning - Fix the PHP SOAP warning Ideal skills: - Proficiency in PHP - Experience dealing with SOAP - Ability to troubleshoot and resolve such issues promptly

Hello, I need a developer with a lot of experience in JavaSCRIPT EXPERT, Python and Socketweb - with the ability to create and solve problems with easy understanding of codes The rest of the details will be given to the correct developer