function confirmDeleteUser(id, type) {
    if (confirm("Are you sure you want to delete this user?")) {
        self.location.href="admin_users.php?delete=" + id + "&type=" + type;
    }
}

function confirmDeleteLesson(id) {
    if (confirm("Are you sure you want to delete this lesson?")) {
        self.location.href="lesson.php?delete=" + id;
    }
}

function checkEnter(e, formName) {
    if (e.keyCode == 13) {
        document.forms[formName].submit();
        return false;
    }
    return true;
}

function focusText(object, defaultValue) {
    if (object.name == 'dummy') {
        object.style.display = 'none';
        var password = document.getElementById('password');
        password.style.display = '';
        password.select();
        password.focus();
    }
    object.value = '';
    return true;
}

function blurText(object, defaultValue) {
    if (object.value == '') {
        object.value = defaultValue;
        object.type = 'text';
    }
    return true;
}

function requiredFieldValidate(id, message) {
    var formItem = document.getElementById(id);
    if (formItem) {
        if (formItem.value == "") {
            showError(id, message);
            return false;
        } else {
            hideError(id);
            return true;
        }
    } else {
        alert("Can't find: " + id);
        return true;
    }
}

function emailValidate(id) {
    var formItem = document.getElementById(id);
    if (formItem) {
        if (formItem.value == '') return 0;
        if (formItem.value.length < 7  || formItem.value.indexOf("@") == -1 || formItem.value.indexOf(".") == -1) {
            showError(id, "Please enter a valid email address");
            return false;
        } else {
            return true;
        }
    } else {
        alert("Can't find: " + id);
        return true;
    }
}

function showError(id, message) {
    var errorID = id + "_error";
    var obj = document.getElementById(errorID);
    if (obj) {
        obj.innerHTML = message;
        obj.style.display = "";
    } else {
        alert("Show error: ID doesn't exist: " + errorID);
    }
}

function hideError(id) {
    var errorID = id + "_error";
    var obj = document.getElementById(errorID);
    if (obj) {
        obj.style.display = "none";
    } else {
        alert("Hide error: ID doesn't exist: " + errorID);
    }
}