Why we can't make script using HTML only?

Answer 1

Because HTML is used for only markup your future web-page. Using HTML you can make submit button, but you can't write what to do when it is pushed. There is no variables in HTML either. To make a site you should know HTML (to markup your page), CSS (to make it beautiful), JavaScript (to write scripts on a client side. For example, to count a sum of two numbers, that a user insert in your input text fields). Besides, you need JS to draw using canvas and to do many other things. To make scripts on a server side you need at least one more programming language. You can use php. If it is necessary on a server side database can be used. In this case you need SQL. For example your page asks to enter login and password. Then server side program should look at database who are you. And then it should make a content accordingly to who you are and its privacy policies.

Answer 2

https://www.sololearn.com/learn/JavaScript/1123/