What are some alternatives?
When comparing dhtmlxSpreadsheet and Google Sheets, you can also consider the following products
ag-Grid - The best HTML5 datagrid in the world
LibreOffice - Calc - LibreOffice Calc is the spreadsheet program you've always needed. A fork of OpenOffice.
EtherCalc - EtherCalc is a web spreadsheet.
Microsoft Office Excel - Microsoft Office Excel is a commercial spreadsheet application.
Apple Numbers - Numbers lets you build beautiful spreadsheets on a Mac, iPad, or iPhone — or on a PC using iWork for iCloud. And it’s compatible with Apple Pencil.