XUL:Attribute:button.type

type: Type: one of the values below; The type of button. If this attribute is not present, a normal button is created. Leave the attribute out for a normal button.

checkbox: This type of button can be in two states. The user can click the button to switch between the states. This is not the same as a checkbox because it looks like a button.
menu: Set the type attribute to the value menu to create a button with a menu popup. Place a menupopup element inside the button in this case. The user may click anywhere on the button to open and close the menu.
menu-button: You can also use the value menu-button to create a button with a menu. Unlike the menu type, this type requires the user to press the arrow to open the menu, but a different command may be invoked when the main part of the button is pressed.
radio: The button acts like a radio button. Only one button in the group can be on a once.
repeat: This button will fire its command event repeatedly while the mouse button is held down. New in Firefox 3

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