decodeURIComponentintermediatedecodeURIComponent('%3Fkey%3Dvalue') // β '?key=value'
// %3F=question markdecodeURIComponent() decodes characters like ? (%3F) that encodeURI would leave intact.
decodeURIComponent('%3Fkey%3Dvalue') decodes to '?key=value'.
Challenge: Verify the decoding.