Q:
Why the print button doesn't appear in report viewer in the case of browsing through the Firefox ?
How to show this button in this browser to print my report?
This is because the print button is an Active-X control and Active-X controls work only with Internet explorer
For the rest of browsers export to pdf or excel and print from the application
In case the entire report renders in one page, you can use the browser print button to print the report
来源：https://stackoverflow.com/questions/7385923/the-print-button-doesnt-appear-in-firefox