function do_submit()
{
	//checking required fields
	if((document.contact_form.fullname.value.length == 0) || (document.contact_form.email.value.length == 0) || (document.contact_form.subject.value.length == 0) || (document.contact_form.message.value.length == 0))
	{
		alert ('You must fill all required fields');
		return false;
	} else {
		if (document.getElementById){

			var myForm = document.getElementById("form");
			var myText = document.getElementById("submit_text");

			if (myForm && myText){
				myForm.style.display = "none";
				myText.style.display = "block";
			}
		}

		document.contact_form.submit();
	}
}