Query String ↔ JSON

Good to know

• A leading ? or # is ignored, so you can paste the tail of a URL as it stands.
• A key that appears more than once becomes an array, and so does one written as tag[]. A key written as filter[colour] becomes a nested object.
• Everything read from a query string is text. A query string carries no types, so 2 arrives as "2".
• Going the other way the brackets come back percent-encoded, which is the correct spelling for a URL even though many servers accept them bare.