What is the purpose of the colon?
e. g.:
Dim objConn : Set objConn = OpenConnection()`
Is the colon used to combine the two statements
Yes this is correct. In VB style languages, including VBScript, the colon is an end of statement token. It allows you to place several statements on the same line.
You can put two (or more) lines of code in one line. It's most often used, as in your example, to declare and set a variable on one line.
Think of it like a semicolon in every other language, except optional.
Yes, the code would work exactly the same on two lines; the colon's just a statement separator.
What you have stated is correct. The purpose of the colon is to combine 2 otherwise separate lines into a single line. It works on most statements, but not all.