Excel to JSONConvert Excel spreadsheets (.xlsx, .xls) to JSON format with sheet selection.

File parsing is handled by the SheetJS (xlsx) library, which reads the uploaded file as an ArrayBuffer and parses the binary spreadsheet format. The library supports Microsoft Office formats (BIFF for .xls, OOXML for .xlsx), OpenDocument (.ods), and other spreadsheet formats. The sheet_to_json() utility converts a worksheet into an array of objects using the first row as keys. Empty rows are typically excluded. Cell values are converted to their JavaScript equivalents: numbers, strings, dates, and booleans. For multi-sheet workbooks, the SheetNames array provides the list of available sheets, and users can select which sheet to convert. The conversion processes only the selected sheet. Performance note: Very large spreadsheets (100,000+ rows) may take several seconds to process in the browser. The xlsx library is optimized for browser use but memory usage scales with file size.