function chklogin(){	
	if(form_login.username.value==""){alert("กรุณากรอก username ด้วย");form_login.username.focus();return false}
	if(form_login.password.value==""){alert("กรุณากรอก password ด้วย");form_login.password.focus();return false}
	
	var j = new ajax();
	j.jaxinit();
	j.addvar("js",1);
	j.addvar("nohf",1);
	j.addvar("username",form_login.username.value);
	j.addvar("password",form_login.password.value);
	j.addvar("mode","chklogin");
	j.addvar("page","users");
	j.processOnly=true;
	j.processajax("index.php");	 
	if(j.responseText==1){
		alert("ยินดีต้อนรับ");
		document.location.href="index.php?page=book";
		return false;
	}else{
		alert("username กับ password ไม่ถูกต้อง");
		return false;
	}
}