function  checkForm(f){	
//firstname
	if(f.cs_firstname.value=="" || f.cs_firstname.value==null){
		window.alert(T_NAME_TYPE);
		f.cs_firstname.focus();
		return false;
	}
//lastname
	if(f.cs_lastname.value=="" || f.cs_lastname.value==null){
		window.alert(T_NAME_TYPE);
		f.cs_lastname.focus();
		return false;
	}
//email -1
	if (!REGEX_EMAIL.test(f.cs_email.value)){
		window.alert(T_EMAIL_TYPE);
		f.cs_email.focus();
		return false;
	}
//time
	if(f.cs_phone.value=="" || isNaN(f.cs_phone.value)){
		window.alert(T_PHONE_TYPE);
		f.cs_phone.focus();
		return false;
	}
	return esnc_aform;
}