In this paper, we are trying to introduce a method of selection of some web pages from a web application, which will be verified by using different validating mechanisms. The number of selected web pages cannot be higher than a previously established constant. The method of selection of these web pages must assure the highest possible quality of the verification of the entire application. The error detection of these web pages will automatically lead to the error detection in other pages. This fact will be realised by using an equivalence relation among the web pages of the web application.