Excel 2000 makes it easier than ever to save a workbook in HTML format. After creating your workbook, use the File*Save as Web Page command. Specify what you want to save (a single worksheet or the entire workbook) and click the Save button. The result will be an HTML document and, possibly, a directory containing ancillary files; the number of such files varies with the complexity of your workbook. These files contain information, such as graphics and macros, that can't be stored in standard HTML format. When you post the HTML file on a Web server, you must include the files in the associated directory. You'll find that the HTML file survives "round-tripping": in other words, if you reopen the HTML file in Excel 2000, every element will be intact.

Alternatively, you may save your workbook (single sheet only) in HTML format with "interactivity". When you open the HTML file in a compatible browser (IE 4.01 or later, not Netscape Navigator), you can interact with the Web page: enter data, recalculate formulas, update charts and pivot tables, and so on. Before you get too excited, however, be warned that this feature has some serious limitations. Many common formatting options are not retained, and features like array formulas, macros and outlining aren't supported.

FIGURE 1 shows a simple interactive HTML document. This worksheet calculates the dates for various US holidays, using the year entered in cell C3. I used the File*Save as Web Page command to save the workbook in HTML format. In the Save As dialogue box, I checked the box labelled Add interactivity.

To try out this example, point your browser to www.j-walk.com/holidays.htm. When the page loads, you'll be able to enter a different year in cell C3, and the formulae will display the calculated dates. The sheet isn't protected, so you can even examine the formulae. There's no formula bar, so you will have to press <F2> to view the formula in the active cell.

To view an interactive Excel file, you need Internet Explorer 4.01 or later, and Microsoft Office Web Components (included with most versions of Office 2000) must be installed on your system.

Note: If you have Excel 2000 installed on your system and you receive an error message when attempting to view an interactive spreadsheet on the Web, check your version of the software. For reasons known only to Microsoft, the Office Web components aren't included with the Small Business Edition of Office 2000 or with the stand-alone version of Excel 2000. In other words, your copy of Excel 2000 may be lacking one of the key selling points of the product. According to Microsoft, you can legally install the Office Web Components if you own Office 2000 Small Business Edition and if someone in your organisation has a licence for Microsoft Office 2000 Premium, Professional or Standard, or Microsoft Access 2000. If you have only the stand-alone version of Excel, you cannot install the Web Components.