Adding data to an existing Web page
Sometimes you'll want to save a worksheet as part of an existing HTML file rather than as a new HTML file. Just keep in mind that anytime you add a worksheet to an existing Web page, Excel appends the worksheet data to the very bottom of the existing Web page.
The steps for saving a worksheet as part of an existing HTML file are virtually the same as for saving a worksheet in a new file. The only difference is that in the File Name text box in Save As dialog box, you enter or select the name of the existing file to which the new HTML version of the worksheet will be appended. Also, when you click the Save button, an Alert dialog box appears in which you click the Add to File button rather than the Replace File or Cancel button.
You can't save an entire workbook as part of an existing Web page. When you select the name of an existing HTML file when the Entire Workbook option button is selected, your only choices are to replace the file or cancel the action of saving it. If you click the Replace File button in the Alert dialog box that appears, you end up getting rid of the original file rather than adding new data to it!