diff --git a/pagetop/src/base/component/anchor.rs b/pagetop/src/base/component/anchor.rs
index 4f021ce2..d157b942 100644
--- a/pagetop/src/base/component/anchor.rs
+++ b/pagetop/src/base/component/anchor.rs
@@ -28,10 +28,10 @@ type AnchorHtml = TypedComponent<L10n>;
 pub struct Anchor {
     weight     : Weight,
     renderable : Renderable,
-    id         : IdentifierValue,
-    classes    : Classes,
+    id         : OptionId,
+    classes    : OptionClasses,
     anchor_type: AnchorType,
-    href       : AttributeValue,
+    href       : OptionString,
     html       : AnchorHtml,
     left_icon  : AnchorIcon,
     right_icon : AnchorIcon,
@@ -85,18 +85,18 @@ impl ComponentTrait for Anchor {
 }
 
 impl Anchor {
-    pub fn link(href: &str, html: L10n) -> Self {
+    pub fn link(href: impl Into<String>, html: L10n) -> Self {
         Anchor::new().with_href(href).with_html(html)
     }
 
-    pub fn button(href: &str, html: L10n) -> Self {
+    pub fn button(href: impl Into<String>, html: L10n) -> Self {
         Anchor::new()
             .with_type(AnchorType::Button)
             .with_href(href)
             .with_html(html)
     }
 
-    pub fn location(id: &str) -> Self {
+    pub fn location(id: impl Into<String>) -> Self {
         Anchor::new().with_type(AnchorType::Location).with_id(id)
     }
 
@@ -115,7 +115,7 @@ impl Anchor {
     }
 
     #[fn_builder]
-    pub fn alter_id(&mut self, id: &str) -> &mut Self {
+    pub fn alter_id(&mut self, id: impl Into<String>) -> &mut Self {
         self.id.alter_value(id);
         self
     }
@@ -140,7 +140,7 @@ impl Anchor {
     }
 
     #[fn_builder]
-    pub fn alter_href(&mut self, href: &str) -> &mut Self {
+    pub fn alter_href(&mut self, href: impl Into<String>) -> &mut Self {
         self.href.alter_value(href);
         self
     }
@@ -177,7 +177,7 @@ impl Anchor {
 
     // Anchor GETTERS.
 
-    pub fn classes(&self) -> &Classes {
+    pub fn classes(&self) -> &OptionClasses {
         &self.classes
     }
 
@@ -185,7 +185,7 @@ impl Anchor {
         &self.anchor_type
     }
 
-    pub fn href(&self) -> &AttributeValue {
+    pub fn href(&self) -> &OptionString {
         &self.href
     }
 
diff --git a/pagetop/src/base/component/block.rs b/pagetop/src/base/component/block.rs
index f83ff261..ab3b1370 100644
--- a/pagetop/src/base/component/block.rs
+++ b/pagetop/src/base/component/block.rs
@@ -4,14 +4,16 @@ new_handle!(COMPONENT_BLOCK);
 
 actions_for_component!(Block);
 
+type BlockTitle = TypedComponent<L10n>;
+
 #[rustfmt::skip]
 #[derive(Default)]
 pub struct Block {
     weight    : Weight,
     renderable: Renderable,
-    id        : IdentifierValue,
-    classes   : Classes,
-    title     : AttributeValue,
+    id        : OptionId,
+    classes   : OptionClasses,
+    title     : BlockTitle,
     stuff     : ArcComponents,
     template  : String,
 }
@@ -45,7 +47,7 @@ impl ComponentTrait for Block {
         let id = cx.required_id::<Block>(self.id());
         PrepareMarkup::With(html! {
             div id=(id) class=[self.classes().get()] {
-                @if let Some(title) = self.title().get() {
+                @if let Some(title) = self.title().get().into_string(cx) {
                     h2 class="block-title" { (title) }
                 }
                 div class="block-body" {
@@ -64,7 +66,7 @@ impl Block {
     // Block BUILDER.
 
     #[fn_builder]
-    pub fn alter_id(&mut self, id: &str) -> &mut Self {
+    pub fn alter_id(&mut self, id: impl Into<String>) -> &mut Self {
         self.id.alter_value(id);
         self
     }
@@ -88,8 +90,8 @@ impl Block {
     }
 
     #[fn_builder]
-    pub fn alter_title(&mut self, title: &str) -> &mut Self {
-        self.title.alter_value(title);
+    pub fn alter_title(&mut self, title: L10n) -> &mut Self {
+        self.title.set(title);
         self
     }
 
@@ -112,11 +114,11 @@ impl Block {
 
     // Block GETTERS.
 
-    pub fn classes(&self) -> &Classes {
+    pub fn classes(&self) -> &OptionClasses {
         &self.classes
     }
 
-    pub fn title(&self) -> &AttributeValue {
+    pub fn title(&self) -> &BlockTitle {
         &self.title
     }
 
diff --git a/pagetop/src/base/component/form_element/button.rs b/pagetop/src/base/component/form_element/button.rs
index ee869382..94b422dd 100644
--- a/pagetop/src/base/component/form_element/button.rs
+++ b/pagetop/src/base/component/form_element/button.rs
@@ -17,12 +17,12 @@ type ButtonValue = TypedComponent<L10n>;
 pub struct Button {
     weight     : Weight,
     renderable : Renderable,
-    classes    : Classes,
+    classes    : OptionClasses,
     button_type: ButtonType,
-    name       : AttributeValue,
+    name       : OptionString,
     value      : ButtonValue,
-    autofocus  : AttributeValue,
-    disabled   : AttributeValue,
+    autofocus  : OptionString,
+    disabled   : OptionString,
     template   : String,
 }
 
@@ -146,7 +146,7 @@ impl Button {
 
     // Button GETTERS.
 
-    pub fn classes(&self) -> &Classes {
+    pub fn classes(&self) -> &OptionClasses {
         &self.classes
     }
 
@@ -154,7 +154,7 @@ impl Button {
         &self.button_type
     }
 
-    pub fn name(&self) -> &AttributeValue {
+    pub fn name(&self) -> &OptionString {
         &self.name
     }
 
@@ -162,11 +162,11 @@ impl Button {
         &self.value
     }
 
-    pub fn autofocus(&self) -> &AttributeValue {
+    pub fn autofocus(&self) -> &OptionString {
         &self.autofocus
     }
 
-    pub fn disabled(&self) -> &AttributeValue {
+    pub fn disabled(&self) -> &OptionString {
         &self.disabled
     }
 
diff --git a/pagetop/src/base/component/form_element/date.rs b/pagetop/src/base/component/form_element/date.rs
index 17e70845..f9b71c89 100644
--- a/pagetop/src/base/component/form_element/date.rs
+++ b/pagetop/src/base/component/form_element/date.rs
@@ -7,17 +7,17 @@ new_handle!(COMPONENT_DATE);
 pub struct Date {
     weight      : Weight,
     renderable  : Renderable,
-    classes     : Classes,
-    name        : AttributeValue,
-    value       : AttributeValue,
-    label       : AttributeValue,
-    placeholder : AttributeValue,
-    autofocus   : AttributeValue,
-    autocomplete: AttributeValue,
-    disabled    : AttributeValue,
-    readonly    : AttributeValue,
-    required    : AttributeValue,
-    help_text   : AttributeValue,
+    classes     : OptionClasses,
+    name        : OptionString,
+    value       : OptionString,
+    label       : OptionString,
+    placeholder : OptionString,
+    autofocus   : OptionString,
+    autocomplete: OptionString,
+    disabled    : OptionString,
+    readonly    : OptionString,
+    required    : OptionString,
+    help_text   : OptionString,
     template    : String,
 }
 
@@ -176,47 +176,47 @@ impl Date {
 
     // Date GETTERS.
 
-    pub fn classes(&self) -> &Classes {
+    pub fn classes(&self) -> &OptionClasses {
         &self.classes
     }
 
-    pub fn name(&self) -> &AttributeValue {
+    pub fn name(&self) -> &OptionString {
         &self.name
     }
 
-    pub fn value(&self) -> &AttributeValue {
+    pub fn value(&self) -> &OptionString {
         &self.value
     }
 
-    pub fn label(&self) -> &AttributeValue {
+    pub fn label(&self) -> &OptionString {
         &self.label
     }
 
-    pub fn placeholder(&self) -> &AttributeValue {
+    pub fn placeholder(&self) -> &OptionString {
         &self.placeholder
     }
 
-    pub fn autofocus(&self) -> &AttributeValue {
+    pub fn autofocus(&self) -> &OptionString {
         &self.autofocus
     }
 
-    pub fn autocomplete(&self) -> &AttributeValue {
+    pub fn autocomplete(&self) -> &OptionString {
         &self.autocomplete
     }
 
-    pub fn disabled(&self) -> &AttributeValue {
+    pub fn disabled(&self) -> &OptionString {
         &self.disabled
     }
 
-    pub fn readonly(&self) -> &AttributeValue {
+    pub fn readonly(&self) -> &OptionString {
         &self.readonly
     }
 
-    pub fn required(&self) -> &AttributeValue {
+    pub fn required(&self) -> &OptionString {
         &self.required
     }
 
-    pub fn help_text(&self) -> &AttributeValue {
+    pub fn help_text(&self) -> &OptionString {
         &self.help_text
     }
 
diff --git a/pagetop/src/base/component/form_element/form.rs b/pagetop/src/base/component/form_element/form.rs
index f4da8da7..3767d0b7 100644
--- a/pagetop/src/base/component/form_element/form.rs
+++ b/pagetop/src/base/component/form_element/form.rs
@@ -16,10 +16,10 @@ pub enum FormMethod {
 pub struct Form {
     weight    : Weight,
     renderable: Renderable,
-    id        : IdentifierValue,
-    classes   : Classes,
-    action    : AttributeValue,
-    charset   : AttributeValue,
+    id        : OptionId,
+    classes   : OptionClasses,
+    action    : OptionString,
+    charset   : OptionString,
     method    : FormMethod,
     stuff     : ArcComponents,
     template  : String,
@@ -91,7 +91,7 @@ impl Form {
     }
 
     #[fn_builder]
-    pub fn alter_id(&mut self, id: &str) -> &mut Self {
+    pub fn alter_id(&mut self, id: impl Into<String>) -> &mut Self {
         self.id.alter_value(id);
         self
     }
@@ -139,15 +139,15 @@ impl Form {
 
     // Form GETTERS.
 
-    pub fn classes(&self) -> &Classes {
+    pub fn classes(&self) -> &OptionClasses {
         &self.classes
     }
 
-    pub fn action(&self) -> &AttributeValue {
+    pub fn action(&self) -> &OptionString {
         &self.action
     }
 
-    pub fn charset(&self) -> &AttributeValue {
+    pub fn charset(&self) -> &OptionString {
         &self.charset
     }
 
diff --git a/pagetop/src/base/component/form_element/hidden.rs b/pagetop/src/base/component/form_element/hidden.rs
index 79264c01..25807a45 100644
--- a/pagetop/src/base/component/form_element/hidden.rs
+++ b/pagetop/src/base/component/form_element/hidden.rs
@@ -6,8 +6,8 @@ new_handle!(COMPONENT_HIDDEN);
 #[derive(Default)]
 pub struct Hidden {
     weight: Weight,
-    name  : NameValue,
-    value : AttributeValue,
+    name  : OptionName,
+    value : OptionString,
 }
 
 impl ComponentTrait for Hidden {
@@ -58,11 +58,11 @@ impl Hidden {
 
     // Hidden GETTERS.
 
-    pub fn name(&self) -> &NameValue {
+    pub fn name(&self) -> &OptionName {
         &self.name
     }
 
-    pub fn value(&self) -> &AttributeValue {
+    pub fn value(&self) -> &OptionString {
         &self.value
     }
 }
diff --git a/pagetop/src/base/component/form_element/input.rs b/pagetop/src/base/component/form_element/input.rs
index 7a06dda5..00595fe3 100644
--- a/pagetop/src/base/component/form_element/input.rs
+++ b/pagetop/src/base/component/form_element/input.rs
@@ -21,20 +21,20 @@ type InputHelpText = TypedComponent<L10n>;
 pub struct Input {
     weight      : Weight,
     renderable  : Renderable,
-    classes     : Classes,
+    classes     : OptionClasses,
     input_type  : InputType,
-    name        : NameValue,
-    value       : AttributeValue,
+    name        : OptionName,
+    value       : OptionString,
     label       : InputLabel,
     size        : Option<u16>,
     minlength   : Option<u16>,
     maxlength   : Option<u16>,
-    placeholder : AttributeValue,
-    autofocus   : AttributeValue,
-    autocomplete: AttributeValue,
-    disabled    : AttributeValue,
-    readonly    : AttributeValue,
-    required    : AttributeValue,
+    placeholder : OptionString,
+    autofocus   : OptionString,
+    autocomplete: OptionString,
+    disabled    : OptionString,
+    readonly    : OptionString,
+    required    : OptionString,
     help_text   : InputHelpText,
     template    : String,
 }
@@ -282,7 +282,7 @@ impl Input {
 
     // Input GETTERS.
 
-    pub fn classes(&self) -> &Classes {
+    pub fn classes(&self) -> &OptionClasses {
         &self.classes
     }
 
@@ -290,11 +290,11 @@ impl Input {
         &self.input_type
     }
 
-    pub fn name(&self) -> &NameValue {
+    pub fn name(&self) -> &OptionName {
         &self.name
     }
 
-    pub fn value(&self) -> &AttributeValue {
+    pub fn value(&self) -> &OptionString {
         &self.value
     }
 
@@ -314,27 +314,27 @@ impl Input {
         self.maxlength
     }
 
-    pub fn placeholder(&self) -> &AttributeValue {
+    pub fn placeholder(&self) -> &OptionString {
         &self.placeholder
     }
 
-    pub fn autofocus(&self) -> &AttributeValue {
+    pub fn autofocus(&self) -> &OptionString {
         &self.autofocus
     }
 
-    pub fn autocomplete(&self) -> &AttributeValue {
+    pub fn autocomplete(&self) -> &OptionString {
         &self.autocomplete
     }
 
-    pub fn disabled(&self) -> &AttributeValue {
+    pub fn disabled(&self) -> &OptionString {
         &self.disabled
     }
 
-    pub fn readonly(&self) -> &AttributeValue {
+    pub fn readonly(&self) -> &OptionString {
         &self.readonly
     }
 
-    pub fn required(&self) -> &AttributeValue {
+    pub fn required(&self) -> &OptionString {
         &self.required
     }
 
diff --git a/pagetop/src/base/component/heading.rs b/pagetop/src/base/component/heading.rs
index 3b87dd5e..3c07bb51 100644
--- a/pagetop/src/base/component/heading.rs
+++ b/pagetop/src/base/component/heading.rs
@@ -32,8 +32,8 @@ type HeadingText = TypedComponent<L10n>;
 pub struct Heading {
     weight      : Weight,
     renderable  : Renderable,
-    id          : IdentifierValue,
-    classes     : Classes,
+    id          : OptionId,
+    classes     : OptionClasses,
     heading_type: HeadingType,
     text        : HeadingText,
     display     : HeadingDisplay,
@@ -127,7 +127,7 @@ impl Heading {
     }
 
     #[fn_builder]
-    pub fn alter_id(&mut self, id: &str) -> &mut Self {
+    pub fn alter_id(&mut self, id: impl Into<String>) -> &mut Self {
         self.id.alter_value(id);
         self
     }
@@ -177,7 +177,7 @@ impl Heading {
 
     // Paragraph GETTERS.
 
-    pub fn classes(&self) -> &Classes {
+    pub fn classes(&self) -> &OptionClasses {
         &self.classes
     }
 
diff --git a/pagetop/src/base/component/icon.rs b/pagetop/src/base/component/icon.rs
index 0b45ea08..a90a70e3 100644
--- a/pagetop/src/base/component/icon.rs
+++ b/pagetop/src/base/component/icon.rs
@@ -8,7 +8,7 @@ pub struct Icon {
     weight    : Weight,
     renderable: Renderable,
     icon_name : String,
-    classes   : Classes,
+    classes   : OptionClasses,
 }
 
 impl ComponentTrait for Icon {
@@ -73,7 +73,7 @@ impl Icon {
         self.icon_name.as_str()
     }
 
-    pub fn classes(&self) -> &Classes {
+    pub fn classes(&self) -> &OptionClasses {
         &self.classes
     }
 }
diff --git a/pagetop/src/base/component/image.rs b/pagetop/src/base/component/image.rs
index ddff8144..6cf1c632 100644
--- a/pagetop/src/base/component/image.rs
+++ b/pagetop/src/base/component/image.rs
@@ -20,9 +20,9 @@ pub enum ImageSize {
 pub struct Image {
     weight    : Weight,
     renderable: Renderable,
-    id        : IdentifierValue,
-    classes   : Classes,
-    source    : AttributeValue,
+    id        : OptionId,
+    classes   : OptionClasses,
+    source    : OptionString,
     size      : ImageSize,
 }
 
@@ -101,7 +101,7 @@ impl Image {
     }
 
     #[fn_builder]
-    pub fn alter_id(&mut self, id: &str) -> &mut Self {
+    pub fn alter_id(&mut self, id: impl Into<String>) -> &mut Self {
         self.id.alter_value(id);
         self
     }
@@ -126,11 +126,11 @@ impl Image {
 
     // Image GETTERS.
 
-    pub fn classes(&self) -> &Classes {
+    pub fn classes(&self) -> &OptionClasses {
         &self.classes
     }
 
-    pub fn source(&self) -> &AttributeValue {
+    pub fn source(&self) -> &OptionString {
         &self.source
     }
 
diff --git a/pagetop/src/base/component/paragraph.rs b/pagetop/src/base/component/paragraph.rs
index b968140f..b51de2fa 100644
--- a/pagetop/src/base/component/paragraph.rs
+++ b/pagetop/src/base/component/paragraph.rs
@@ -18,8 +18,8 @@ pub enum ParagraphDisplay {
 pub struct Paragraph {
     weight    : Weight,
     renderable: Renderable,
-    id        : IdentifierValue,
-    classes   : Classes,
+    id        : OptionId,
+    classes   : OptionClasses,
     stuff     : ArcComponents,
     display   : ParagraphDisplay,
     template  : String,
@@ -78,7 +78,7 @@ impl Paragraph {
     }
 
     #[fn_builder]
-    pub fn alter_id(&mut self, id: &str) -> &mut Self {
+    pub fn alter_id(&mut self, id: impl Into<String>) -> &mut Self {
         self.id.alter_value(id);
         self
     }
@@ -126,7 +126,7 @@ impl Paragraph {
 
     // Paragraph GETTERS.
 
-    pub fn classes(&self) -> &Classes {
+    pub fn classes(&self) -> &OptionClasses {
         &self.classes
     }
 
diff --git a/pagetop/src/base/component/wrapper.rs b/pagetop/src/base/component/wrapper.rs
index 339302fc..aa4d2e36 100644
--- a/pagetop/src/base/component/wrapper.rs
+++ b/pagetop/src/base/component/wrapper.rs
@@ -19,9 +19,9 @@ pub enum WrapperType {
 pub struct Wrapper {
     weight       : Weight,
     renderable   : Renderable,
-    id           : IdentifierValue,
-    classes      : Classes,
-    inner_classes: Classes,
+    id           : OptionId,
+    classes      : OptionClasses,
+    inner_classes: OptionClasses,
     wrapper_type : WrapperType,
     stuff        : ArcComponents,
     template     : String,
@@ -137,7 +137,7 @@ impl Wrapper {
     }
 
     #[fn_builder]
-    pub fn alter_id(&mut self, id: &str) -> &mut Self {
+    pub fn alter_id(&mut self, id: impl Into<String>) -> &mut Self {
         self.id.alter_value(id);
         self
     }
@@ -173,11 +173,11 @@ impl Wrapper {
 
     // Wrapper GETTERS.
 
-    pub fn classes(&self) -> &Classes {
+    pub fn classes(&self) -> &OptionClasses {
         &self.classes
     }
 
-    pub fn inner_classes(&self) -> &Classes {
+    pub fn inner_classes(&self) -> &OptionClasses {
         &self.inner_classes
     }
 
diff --git a/pagetop/src/html.rs b/pagetop/src/html.rs
index 34cb7cdb..8e8e43ef 100644
--- a/pagetop/src/html.rs
+++ b/pagetop/src/html.rs
@@ -13,17 +13,17 @@ pub use assets::Assets;
 mod favicon;
 pub use favicon::Favicon;
 
-mod identifier;
-pub use identifier::IdentifierValue;
+mod opt_id;
+pub use opt_id::OptionId;
 
-mod name;
-pub use name::NameValue;
+mod opt_name;
+pub use opt_name::OptionName;
 
-mod attribute;
-pub use attribute::AttributeValue;
+mod opt_string;
+pub use opt_string::OptionString;
 
-mod classes;
-pub use classes::{Classes, ClassesOp};
+mod opt_classes;
+pub use opt_classes::{ClassesOp, OptionClasses};
 
 pub mod unit;
 
@@ -45,7 +45,13 @@ impl PrepareMarkup {
     pub fn into_string(self) -> Option<String> {
         match self {
             PrepareMarkup::None => None,
-            PrepareMarkup::Text(text) => Some(text.to_string()),
+            PrepareMarkup::Text(text) => {
+                if text.is_empty() {
+                    None
+                } else {
+                    Some(text.to_string())
+                }
+            }
             PrepareMarkup::With(markup) => Some(markup.into_string()),
         }
     }
diff --git a/pagetop/src/html/classes.rs b/pagetop/src/html/opt_classes.rs
similarity index 79%
rename from pagetop/src/html/classes.rs
rename to pagetop/src/html/opt_classes.rs
index c7fd6154..3be0c977 100644
--- a/pagetop/src/html/classes.rs
+++ b/pagetop/src/html/opt_classes.rs
@@ -1,4 +1,4 @@
-//! **Classes** implements a *helper* for dynamically adding class names to components.
+//! **OptionClasses** implements a *helper* for dynamically adding class names to components.
 //!
 //! This *helper* differentiates between default classes (generally associated with styles provided
 //! by the theme) and user classes (for customizing components based on application styles).
@@ -18,7 +18,9 @@ pub enum ClassesOp {
     Add,
     Remove,
     Replace(String),
+    Toggle,
     Reset,
+    Clear,
 }
 
 #[derive(Clone, PartialEq)]
@@ -28,14 +30,14 @@ enum ClassType {
 }
 
 #[derive(Default)]
-pub struct Classes(Vec<(String, ClassType)>);
+pub struct OptionClasses(Vec<(String, ClassType)>);
 
-impl Classes {
+impl OptionClasses {
     pub fn new() -> Self {
-        Classes::default()
+        OptionClasses::default()
     }
 
-    // Classes BUILDER.
+    // OptionClasses BUILDER.
 
     #[fn_builder]
     pub fn alter_value(&mut self, op: ClassesOp, classes: impl Into<String>) -> &mut Self {
@@ -58,8 +60,8 @@ impl Classes {
                 self.add(&classes, self.0.len(), ClassType::User);
             }
             ClassesOp::Remove => {
-                for name in classes {
-                    self.0.retain(|(c, _)| c.ne(&name.to_string()));
+                for class in classes {
+                    self.0.retain(|(c, _)| c.ne(&class.to_string()));
                 }
             }
             ClassesOp::Replace(classes_to_replace) => {
@@ -79,9 +81,23 @@ impl Classes {
                 }
                 self.add(&classes, pos, class_type);
             }
+            ClassesOp::Toggle => {
+                for class in classes {
+                    if !class.is_empty() {
+                        if let Some(pos) = self.0.iter().position(|(c, _)| c.eq(class)) {
+                            self.0.remove(pos);
+                        } else {
+                            self.0.push((class.to_string(), ClassType::User));
+                        }
+                    }
+                }
+            }
             ClassesOp::Reset => {
                 self.0.retain(|(_, t)| t.ne(&ClassType::User));
             }
+            ClassesOp::Clear => {
+                self.0.clear();
+            }
         }
         self
     }
@@ -96,7 +112,7 @@ impl Classes {
         }
     }
 
-    // Classes GETTERS.
+    // OptionClasses GETTERS.
 
     pub fn exists(&self, class: impl Into<String>) -> bool {
         let class: String = class.into();
diff --git a/pagetop/src/html/name.rs b/pagetop/src/html/opt_id.rs
similarity index 52%
rename from pagetop/src/html/name.rs
rename to pagetop/src/html/opt_id.rs
index c3f2af12..fbc02f0d 100644
--- a/pagetop/src/html/name.rs
+++ b/pagetop/src/html/opt_id.rs
@@ -1,22 +1,22 @@
 use crate::fn_builder;
 
 #[derive(Default)]
-pub struct NameValue(String);
+pub struct OptionId(String);
 
-impl NameValue {
+impl OptionId {
     pub fn new() -> Self {
-        NameValue::default()
+        OptionId::default()
     }
 
-    // NameValue BUILDER.
+    // OptionId BUILDER.
 
     #[fn_builder]
-    pub fn alter_value(&mut self, value: &str) -> &mut Self {
-        self.0 = value.trim().replace(' ', "_");
+    pub fn alter_value(&mut self, value: impl Into<String>) -> &mut Self {
+        self.0 = value.into().trim().replace(' ', "_");
         self
     }
 
-    // NameValue GETTERS.
+    // OptionId GETTERS.
 
     pub fn get(&self) -> Option<String> {
         if self.0.is_empty() {
diff --git a/pagetop/src/html/attribute.rs b/pagetop/src/html/opt_name.rs
similarity index 51%
rename from pagetop/src/html/attribute.rs
rename to pagetop/src/html/opt_name.rs
index 965e8beb..1e811c33 100644
--- a/pagetop/src/html/attribute.rs
+++ b/pagetop/src/html/opt_name.rs
@@ -1,22 +1,22 @@
 use crate::fn_builder;
 
 #[derive(Default)]
-pub struct AttributeValue(String);
+pub struct OptionName(String);
 
-impl AttributeValue {
+impl OptionName {
     pub fn new() -> Self {
-        AttributeValue::default()
+        OptionName::default()
     }
 
-    // AttributeValue BUILDER.
+    // OptionName BUILDER.
 
     #[fn_builder]
-    pub fn alter_value(&mut self, value: &str) -> &mut Self {
-        self.0 = value.trim().to_owned();
+    pub fn alter_value(&mut self, value: impl Into<String>) -> &mut Self {
+        self.0 = value.into().trim().replace(' ', "_");
         self
     }
 
-    // AttributeValue GETTERS.
+    // OptionName GETTERS.
 
     pub fn get(&self) -> Option<String> {
         if self.0.is_empty() {
diff --git a/pagetop/src/html/identifier.rs b/pagetop/src/html/opt_string.rs
similarity index 50%
rename from pagetop/src/html/identifier.rs
rename to pagetop/src/html/opt_string.rs
index 90f8295b..aa872b3a 100644
--- a/pagetop/src/html/identifier.rs
+++ b/pagetop/src/html/opt_string.rs
@@ -1,22 +1,22 @@
 use crate::fn_builder;
 
 #[derive(Default)]
-pub struct IdentifierValue(String);
+pub struct OptionString(String);
 
-impl IdentifierValue {
+impl OptionString {
     pub fn new() -> Self {
-        IdentifierValue::default()
+        OptionString::default()
     }
 
-    // IdentifierValue BUILDER.
+    // OptionString BUILDER.
 
     #[fn_builder]
-    pub fn alter_value(&mut self, value: &str) -> &mut Self {
-        self.0 = value.trim().replace(' ', "_");
+    pub fn alter_value(&mut self, value: impl Into<String>) -> &mut Self {
+        self.0 = value.into().trim().to_owned();
         self
     }
 
-    // IdentifierValue GETTERS.
+    // OptionString GETTERS.
 
     pub fn get(&self) -> Option<String> {
         if self.0.is_empty() {
diff --git a/pagetop/src/response/page.rs b/pagetop/src/response/page.rs
index 0425dbf0..e40ad2a7 100644
--- a/pagetop/src/response/page.rs
+++ b/pagetop/src/response/page.rs
@@ -3,7 +3,7 @@ use crate::base::component::L10n;
 use crate::core::component::{ArcComponent, ComponentTrait, TypedComponent};
 use crate::core::component::{Context, ContextOp};
 use crate::core::theme::ComponentsRegions;
-use crate::html::{html, Classes, ClassesOp, Favicon, Markup, DOCTYPE};
+use crate::html::{html, ClassesOp, Favicon, Markup, OptionClasses, DOCTYPE};
 use crate::response::fatal_error::FatalError;
 use crate::{fn_builder, service};
 
@@ -22,7 +22,7 @@ pub struct Page {
     properties  : Vec<(&'static str, &'static str)>,
     favicon     : Option<Favicon>,
     context     : Context,
-    body_classes: Classes,
+    body_classes: OptionClasses,
     regions     : ComponentsRegions,
     template    : String,
 }
@@ -37,7 +37,7 @@ impl Page {
             properties  : Vec::new(),
             favicon     : None,
             context     : Context::new(request),
-            body_classes: Classes::new().with_value(ClassesOp::SetDefault, "body"),
+            body_classes: OptionClasses::new().with_value(ClassesOp::SetDefault, "body"),
             regions     : ComponentsRegions::new(),
             template    : "default".to_owned(),
         }
@@ -125,7 +125,7 @@ impl Page {
         &mut self.context
     }
 
-    pub fn body_classes(&self) -> &Classes {
+    pub fn body_classes(&self) -> &OptionClasses {
         &self.body_classes
     }