A dialog for entry of uniform resource locators is provided with options, selected by actuation of a radio button, for entering blocks containing a resource identifier, a domain identifier, and a filename extension. The block text is visually distinguished from text entered by single characters from a physical or virtual keyboard. Once entered, the blocks are treated in a unitary manner for the purposes of deletion or substitution, with backspaces or deletes removing the entire block add selection of alternative options replacing the entire block. Character strings entered manually may be compared to the text blocks associated with the options provided and, when a match is identified, replaced with the block form to facilitate form checking of the composed uniform resource locator before returning it to the underlying application.