function chk_data() {
	if (document.contact_form.con_name.value=="")
	{
		alert("Input the name");
		document.contact_form.con_name.focus();
		return false;
	}
	if (document.contact_form.con_email.value=="")
	{
		alert("input the E-Mail");
		document.contact_form.con_email.focus();
		return false;
	}
	if (document.contact_form.con_detail.value=="")
	{
		alert("input the content");
		document.contact_form.con_detail.focus();
		return false;
	}
}