JavaScript Uncaught Error in Chrome Console

my error is: Uncaught: TypeError: undefined is not a function.

I am trying to automatically fill a form without hitting submit (I can do that manually, as there is no class or ID on the submit button--then it will re-enter the next set of information after I hit it.) I am also unsure how to do the wait function properly. I have looked it up and tried a few various ways to no avail.

var qu = ["Do they offer whois privacy for domain registrations? free or at cost?"];
var an = ["Yes, so and so offers domain privacy options for domain registration."];
var q = document.getElementByName("question");
var a = document.getElementByName("answer");
var i = 0;
var delay = 2500;

do {
    q.value = qu[i];
    a.value = an[i];
    i++;
} while (i < qu.length)

Thanks!