PromptBox Show Method
Displays a prompt box.
R←I PromptBox.Show ''
or
R←PromptBox.Show I
I is the PromptBox instance. R is '0'.
This method does not wait, and generally should be the last line of a callback, with no following code. All action must be handled in the OnOk and OnCancel callback functions.
See the HTMLDocument Prompt method for easiest use of the AlertBox, encapsulating the New and Show methods.