// prefetch images if browser understands image storage
var button_book_now_up = new Image();
var button_book_now_over = new Image();
var button_login_up = new Image();
var button_login_over = new Image();
var button_quick_quote_up = new Image();
var button_quick_quote_over = new Image();
function prefectchImg() {
  if (document.images) {
    button_book_now_up.src = "images/button_book_now.gif";
    button_book_now_over.src = "images/button_book_now_dn.gif";
    button_login_up.src = "images/button_login.gif";
    button_login_over.src = "images/button_login_dn.gif";
    button_quick_quote_up.src = "images/button_quick_quote.gif";
    button_quick_quote_over.src = "images/button_quick_quote_dn.gif";
  }
}

// mouse over
// params:
//   imgNo - image number representing image to change
function over_button(imgNo) {
  if (document.images) {
    if (imgNo === 1) {
      document.getElementById("button_book_now_id").src = button_book_now_over.src
    } else if (imgNo === 2) {
      document.getElementById("button_login_id").src = button_login_over.src
    } else if (imgNo === 3) {
      document.getElementById("button_quick_quote_id").src = button_quick_quote_over.src
    }
  }
}

// mouse up
// params:
//   imgNo - image number representing image to change
function up_button(imgNo) {
  if (document.images) {
    if (imgNo === 1) {
      document.getElementById("button_book_now_id").src = button_book_now_up.src
    } else if (imgNo === 2) {
      document.getElementById("button_login_id").src = button_login_up.src
    } else if (imgNo === 3) {
      document.getElementById("button_quick_quote_id").src = button_quick_quote_up.src
    }
  }
}