Printing from Code

by David Wall

June 17, 2002 —

Every browser has a print function. It's standard user interface stuff
-- just choose Print from the File menu, or click a Print icon on a
toolbar. The appeal of print commands like those is universal
comprehension: Everyone knows how to print using such things. But in
JavaScript, you have the option of printing from within your code, which
means you can design your own print buttons or print in response to user
actions other than clicking.

The command is straightforward -- it's just a method of the Window
object, which you invoke like this:

window.print();

That string has the same effect as a click on the Print button or a trip
through the File menu to the Print command. It'll typically cause the
Print dialog box to appear, and if the user agrees by setting print
options and clicking okay, the whole contents of the window from which
the command was invoked will be sent to the specified printer.

Is it a good idea to deviate from the standard? Possibly, if you want to
increase the odds that something -- such as a license agreement or an
order form -- is printed out. On the other hand, you don't want to annoy
your users by making more windows pop up. The Print dialog is really no
better than an ad window if the user isn't interested in printing.

ITworld