Question, did you actually get a collection when you do
var inpObjs = document.getElementsByName('typeofbike')
My question is, in the HTML code object should have the name typeofbike including the  sings whitout numbers inside. I mean, it's strange. Can you post the HTML to see what we are tallking about?
By the way, geting objects by name do not get you a colection of options that is probably what are you triyng to do casue you mentioned a "select" object.