Mia Perese
Published July 15, 2026
Updated July 15, 2026
3 min
Working with More File Formats: XLS and CSV Support in Spreadsheet Editor
Mia Perese
Summary: WebViewer 12.0 adds native, browser-side support for loading XLS and CSV files directly into the Spreadsheet Editor alongside new interactive chart capabilities. Users can now click, move, and resize charts, with the editor supporting direct loading for all three formats without pre-processing.
Spreadsheet Editor Now Supports XLS and CSV
Part of the Summer 2026 Release, WebViewer 12.0 adds native support for loading XLS and CSV files to Spreadsheet Editor, alongside the existing XLSX support, and adds chart select, move, and resize interactions you can build into your application. You can pass any of these three formats straight to the editor without a pre-processing step, and users get the same editing experience regardless of which format was loaded.
How do I load an XLS or CSV file into a JavaScript spreadsheet editor?
Pass the file to Spreadsheet Editor the way you would an XLSX file. Conversion to XLSX happens in the browser on load, with no configuration or server-side step. Exports can be saved or downloaded as XLSX or PDF, and the original XLS or CSV file in your storage stays unchanged. In practice, a CSV exported from a reporting tool or a legacy XLS can be opened and edited in the browser directly, without converting it first.
What chart interactions are now available in Spreadsheet Editor?
Before this release, Spreadsheet Editor could already render charts built from spreadsheet data and let users edit the underlying data that feeds a chart. In WebViewer 12.0, users can now select a chart by clicking it, move it to a new position, and resize it by dragging its handles. Performance improvements have been made to chart loading and responsiveness.
What’s Not Supported in This Release
Saving back to XLS or CSV format is not supported in this release. Chart creation, chart styling, and chart type changes also aren’t available yet. Support for additional chart features will be evaluated based on customer demand.
How do I get started with XLS and CSV in Spreadsheet Editor?
- Requires WebViewer 12.0 with the Spreadsheet Editor add-on license
- XLS and CSV loading: no new constructor option required; pass the file to the editor as you would any other supported format
- Check out the docs
- Review the release notes
More from this release
XLS and CSV support and chart interactions are part of the Summer 2026 Release. For WebViewer, this release consolidates the WebViewer UI in version 12.0 and adds the TrackedChangeManager API for programmatic tracked changes in DOCX Editor. For the full WebViewer details of the release, see the WebViewer 12.0 blog and the DOCX Editor tracked changes blog.
