If Statement for Function looping incorrectly - if-statement

Question

I am trying to recreate a simple program I made once in Python in VBScript to have it run in a dialog box.
This is the code:
Set objShell = CreateObject("Wscript.Shell")
Function Query()
query = InputBox("Please input the Subreddit you with to navigate to e.g (globaloffensive)", "iixCarbonxZz's Subreddit Finder")
End Function
Do
If query = "" Then
err = MsgBox("Please enter a Valid Subreddit", vbOKOnly + vbExclamation, "Invalid")
Else
objShell.Run("http://www.reddit.com/r/" & query)
WScript.Quit()
End If
Query()
Loop
My problem is this:
The code opens the input text box and if there is nothing in the text box when the OK button is pressed it should bring up the 'err' error message box and then loop. If it gets something in the input box it should use it then close the script.
In practice if I leave the box blank it displays the message, loops back to the input box but then if left blank again skips the if statement and just reloads the input box. If something is input that it can use it skips the if statement and reloads the box the first time and then runs and closes the second time. If prior to this a blank was submitted it will skip the if statement one further time before using the input properly.

Answer 1

Use a variable to store the function's result
Don't use the same name for the variable and the function
Demo:
Option Explicit
Function getQuery()
getQuery = InputBox("Please input the Subreddit you with to navigate to e.g (globaloffensive)", "iixCarbonxZz's Subreddit Finder")
End Function
Dim query
Do
query = getQuery()
If query = "" Then
err = MsgBox("Please enter a Valid Subreddit", vbOKOnly + vbExclamation,"Invalid")
Else
WScript.Echo "http://www.reddit.com/r/" & query
WScript.Quit 0
End If
Loop