Responsive site using flex

Hey, The reason you want to use JS instead of HTML is because with JS you can make certain user limitations, for example not letting submit the page when certain inputs are empty or only allowing passwords that have one uppercase letter and 8 letters long etc. Normally without JS (which works on the client side) validation the user data goes instantly to the server and that will do the validation which takes longer time then doing it on the client side, where you instantly get the feedback and you don't make extra work for the server either. I hope this answered your question!

Hi. JS is used for form validation because of the flexibility and customisations it provides. But, the most important reason is cyber security. HTML code can easily be changed by just changing the code using the inspector. This is not true for javascript. Sending corrupted files to the server can be extremely dangerous. Hope you found this helpful!