var cleaned = Array();
function clean(field)
{
	for (i = 0; i < cleaned.length; i++)
	{
		if (field.name == cleaned[i])
			return;
	}
	field.value = "";
	cleaned[cleaned.length] = field.name;
	
	if (field.name == 'password')
		field.type = 'password';
}

var campos = Array('usuario','password');