// ==UserScript==
// @name        Goodreads Giveaways checkbox (un)checker
// @namespace   Joseph
// @description Checks the "I have read and agree to terms and conditions..." box and unchecks the "Also add this book to my to-read shelf" box.
// @include     https://www.goodreads.com/giveaway/enter/*
// @include     http://www.goodreads.com/giveaway/enter/*
// @version     1
// @grant       none
// @downloadURL none
// ==/UserScript==

var inputs = document.getElementsByTagName("input");
for (var i = 0; i < inputs.length; i++) {
  if (inputs[i].id === "terms") {
    inputs[i].checked = true;
  }  
  if (inputs[i].id === "want_to_read") {
    inputs[i].checked = false;
  }
}