There are many ways you can optimize your website to load faster. few of them are -

    *  optimize image size and lazy load 
       
    *  Use HTTP2 

    *  Load css in head tag and javascript at the bottom, 
        if required load javascript using async/defer
    
    * Minify Css, javascript 

    * Use gzip compression for html 
    
    * Cache your web pages 

    * Reduce redirects

    * Use CDN for static files 

    * Load large data in chunks 

 

Wipro

Software Engineer

Infosys

Full Stack Developer

Website optimisation and few ways you can reduce page load time?

Hypertext Transfer Protocol (HTTP) is a set of standard protocols allowing internet users to exchange website knowledge on www.

**1. Increased performance:** It was designed specifically to speed up page loading and reduce round-trip time (RTT) for resource-intensive websites.

**2. Multiplexing:** Multiplexing is fully implemented in HTTP/2. It means that multiple requests are sent between browsers and servers simultaneously over a single TCP connection. Consequently, several elements of a web page can be delivered via a single TCP connection. As a result, the HTTP/1.1 head-of-line blocking problem is resolved, in which a packet at the front of the line blocks the transmission of other packets.

**3. Handle multiple resources:** With HTTP 1.1, the web pages were manageable simply by using HTML markups and images. But with HTTP 2.0, there are now multiple resources available for web pages, including images, fonts, scripts, and more. HTTP 1.1 was not designed to handle such a large amount of resources today.

**4. Header Compression:** HTTP 2.0 has the ability to compress HTTP headers to reduce overhead. When HTML headers on web pages are compressed, they can be sent between the browser and server in one trip, over a single TCP connection.

**5. Server push:** HTTP/2 servers are able to push resources into a browser's cache even before they are requested. By doing this, browsers can display content without requiring additional requests.

**6. Binary protocols:** HTTP/2 use binary protocols, not textual. HTML/2's binary protocols consume less bandwidth, can be parsed more efficiently, and are less error-prone compared to HTTP/1.1's textual protocols.



Samsung

Senior Software Engineer

Difference between HTTP/2 and HTTP 1.1.

Long polling is a web application development pattern used to emulate pushing data from the server to the client.  When the long polling is used, the client sends a request to the server, and the connection remains intact until the server is ready to send data to the client. The connection will be closed only after the data is sent back to the client or connection timeout occurs.

Cognizant

Frontend Developer

what is long polling?

An Entity Tag, or ETag, is an integral element of HTTP (Hypertext Transfer Protocol): the protocol that facilitates communication between servers and web browsers. Entity Tag is one of the many mechanisms that the Hypertext Transfer Protocol provides for cache validation, allowing conditional requests from a client.

What is an Entity Tag?

Cross-Origin Resource Sharing (CORS) is an HTTP-header based mechanism that allows a server to indicate any origins (domain, scheme, or port) other than its own from which a browser should permit loading resources.

What is CORS?

**Cookies**: 

Cookie data is accessible for both the client and the server

Cookies have an expiry time, and data gets deleted post expiration

Cookies you can store upto 4kb of data

**LocalStorage**:

Data is stored only on the local browser in the client-side machine

There is no expiry in local storage unless the data is manually deleted

Localstorage you can store upto 5mb.

Top Frontend Interview Questions

1. Website optimisation and few ways you can reduce page load time?

2. Difference between HTTP/2 and HTTP 1.1.

3. what is long polling?

4. What is an Entity Tag?

5. What is CORS?

6. What is the difference between cookies and local storage?