The purpose of this stack is to hide or display content, based on any query strings and matching key-value pairs that may be present in the web browser address bar. If a matching key-value pair is found (or a numerical value that falls within a specific min-max range), a block of content within QueryDisplay is displayed. A quick, simple and efficient stack suitable for a whole multitude of possible jobs. There is little that QueryDisplay cannot do. If you are building modern websites or PWAs (progressive web apps) which rely on query strings, this stack is almost essential.