How do web browsers interact with web servers?

Web browsers interact with web servers by sending HTTP requests and receiving HTTP responses.

When you type a URL into your web browser, it initiates a series of events to fetch and display the requested webpage. This process begins with the browser sending an HTTP request to the web server that hosts the website. HTTP, or Hypertext Transfer Protocol, is the protocol used for transferring data over the internet. It defines a set of rules for how messages are formatted and transmitted, and what actions web servers and browsers should take in response to various commands.

The HTTP request sent by the browser includes the method (such as GET, POST, PUT, DELETE), the URL, and other information like headers and body content. The method tells the server what action to perform. For example, a GET request is used to retrieve data from the server, while a POST request is used to send data to the server.

Once the web server receives the HTTP request, it processes it and sends back an HTTP response. This response contains a status code, headers, and the requested content. The status code indicates whether the request was successful or not, and provides additional information about the result of the request. For example, a 200 status code means the request was successful, while a 404 status code means the requested resource could not be found.

The headers in the HTTP response provide additional information about the response, such as the content type, content length, and server information. The requested content, which is usually an HTML document, is included in the body of the response.

Once the browser receives the HTTP response, it parses the HTML, CSS, and JavaScript in the response to render the webpage. It may also send additional HTTP requests for resources referenced in the HTML, such as images, stylesheets, and scripts.

In summary, the interaction between web browsers and web servers is a request-response cycle. The browser sends an HTTP request to the server, the server processes the request and sends back an HTTP response, and the browser processes the response to display the webpage. This cycle is repeated for every resource that the browser needs to load the webpage.