function enviarLogin(){
    bool = false; 
    if(document.getElementById('txtLogin').value == "") {
        bool = false;
        alert("Introduzca su login");
        document.getElementById('txtLogin').focus();
    }
    else{
        bool = true;
    }
    if(bool){ 
        if(document.getElementById('txtPass').value == "") {
            bool = false;
            alert("Introduzca su contraseña");
            document.getElementById('txtPass').focus();
        }
        else{
            bool = true;
        }
    }
	
    if(bool){
        document.getElementById('form').submit();
    }else{
		window.location.href="index.php";	
	}
}