SpreadsheetML, XML Spreadsheet 2003, or XMLSS, is an XML-based format which was introduced in Microsoft Office 2003 as one of the formats which could be chosen in the "Save As" feature to save spreadsheets, though not the default format (which was XLS, a proprietary binary format). This is a different format from the XLSX format introduced in Office 2007, which consists of a ZIP archive of various files including XML. In contrast, SpreadsheetML is a single XML file, uncompressed, and is unable to store all features which can be present in an Excel spreadsheet. The 2007 versions are still capable of loading and saving SpreadsheetML, even if a different XML-based format is the default format. (However, the term "SpreadsheetML" has also sometimes been used to describe XLSX format as well.)
Opening this file format in OpenOffice apparently requires a Java runtime environment.
A SpreadsheetML file has the following header:
<?xml version="1.0"?> <?mso-application progid="Excel.Sheet"?> <Workbook xmlns="urn:schemas-microsoft-com:office:spreadsheet" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet" xmlns:html="http://www.w3.org/TR/REC-html40"> <DocumentProperties xmlns="urn:schemas-microsoft-com:office:office">