var mousePos;
function changeButton(button) {
    mousePos = document[button].src;
    document[button].src = "images/" + button + "_over.gif";
}
function resetButton(button) {
    document[button].src = mousePos;
}

// arrow
function changeArrow(button, over) {
    document[button + "_arrow"].src = "images/arrow" + over + ".gif";
    document[button].src = "images/" + button + over + ".gif";
}

// check blank fields on contact form
function checkBlank(){
  if (document.contact_form.interest.value==null || document.contact_form.interest.value==""
     || document.contact_form.first_name.value==null || document.contact_form.first_name.value==""
     || document.contact_form.last_name.value==null || document.contact_form.last_name.value==""
	 ||document.contact_form.city.value==null || document.contact_form.city.value==""
	 ||document.contact_form.country.value==null || document.contact_form.country.value==""
	 ||document.contact_form.phone.value==null || document.contact_form.phone.value==""
	 ||document.contact_form.email.value==null || document.contact_form.email.value==""
	 ||document.contact_form.question.value==null || document.contact_form.question.value==""){
	   document.contact_form.submit_form.disabled=true;
  }
  else{document.contact_form.submit_form.disabled=false;}
}