Need help in explaining Instr Function code below

Question

Just want to ask why is the output for this line of code '18', I'm not very particular with Instr Function in Lotusscript.

    Dim expview as String
    expview = Instr("OpenAgent&query=&expview=","expview=")
    Print expview

Answer 1

It is index of character in string OpenAgent&query=&expview= from which string expview= starts.