A method, a system and a machine-readable data carrier, which are intended to classify input fields and groups of input fields of a webpage, are described. The method for classifying input fields and groups of input fields of a webpage may include a browser extension that contains program elements Content Script and Background Script and a program recognition module. The method may form a hierarchy of HTML-documents of a webpage. A multicomponent system for classifying input fields and groups of input fields of a webpage may include a processor device and a storage, and a set of instructions that, when executed by the processor, control the processor to form a hierarchy with grouped fields and a report file for HTML-documents of the webpage. The instructions may also identify elements of the HTML-documents on the webpage.