& lt% Option Explicit%> What do you mean, beginner asp:)

Mandatory variable declaration, undeclared variables cannot be used.

Clear choice in writing

If you have a variable that is used without declaration, the system will prompt you that it is wrong.

Option explicit

Private subcommand 1_Click ()

Darken a as a string.

a = "tttt "

MsgBox (a)

End joint

The above contents have been successfully implemented.

Option explicit

Private subcommand 1_Click ()

a = "tttt "

MsgBox (a)

End joint

There is a compilation error in the above program, that is, as long as Option Explicit is used, all variables must be declared. For example, the wrong program has no dim a statement, so it is wrong.

Private subcommand 1_Click ()

a = "tttt "

MsgBox (a)

End joint

This part can also run normally, because there is no option explicit, so you can not declare variables.