Why we should use web-based framework?

A framework is not absolutely necessary: it is “just” one of the tools that is available to help us to develop better and faster website or web applications. It is better because a framework provides us with the certainty that we are developing an application that is in full compliance with the business rules, that is structured, and that is both maintainable and upgradable. It is faster, because it allows developers to save time by re-using generic modules in order to focus on other areas. Without, however, ever being tied to the framework itself.
Web frameworks help us achieve structure in our applications, and they give us additional features we can add to them without too much extra work. Frameworks give us a place to start so that we can focus on features rather than configuration details.
Code is read many more times than it is written, and it is so important when you are working with other developers that they know where the code for certain tasks is being written so they can use it in their own code. The frameworks also have conventions for how the code is written and structured, which standardize how the developers write their code.
A framework will keep the developer from having to spend 2 or 3 days creating an authentication form (which is not a specific task). The time that is saved can be dedicated to more specific components as well as to the corresponding unit tests; giving you solid, sustainable and high quality code. The aim of frameworks is to provide a common structure so that developers don’t have to redo it from scratch and can reuse the code provided. In this way, frameworks allow us to cut out much of the work and save a lot of time. A framework ensures the longevity of our applications. If a development team works as they please, only that particular team will be able to maintain and upgrade the application with ease.