The basics of working with the document object model, which is the basis for the dynamic formation and modification of the content of HTML pages, using the programming language j & # 097; vascript and the jQuery library, are described. The basics of backend development of web programming applications on the server side on the node.js platform are considered. To consolidate and deeper study of the theoretical material, an example of developing an application for performing simple calculations on the server side and dynamically generating the content of HTML pages with the results of these calculations in tabular and graphic form on the client side is considered. It is assumed that the reader has the basics of HTML, CSS and the basic language j & # 097; vascript.