An attribute is extra information to define elements such that <tag attribute="information">
The id attribute is a unique name for an element in the current page
Document Object Model (DOM)
A cross-platform and language-independent interface that treats an HTML document as a tree structure of node objects representing a part of the document
Every element in the DOM is a node
<div> and <span> are generic HTML container widgets
The div tag is a block-level element used for associating and grouping together nested elements, used very often, it's like SKContainer
The span tag is an inline element used for associating and grouping together nested elements, often used for styling
A CSS rule has three parts
selector
declaration block
one or more properties with values
A pattern to select (or find) elements in the DOM
Basic selectors
div { … } select by tag type
.foo { … } select by class name
#a { … } select by element id attribute
[type="text"] { … } select elements matching attribute value
Hierarchical selectors
div > div { … } select child elements by parent-child relationship
div div { … } select child elements by descendant relationship
Pseudo class selectors (there are many more …)
:first-child select first child
:hover select when mouse is over element
Combining selectors
div#a { … } select elements matching all selectors
div, #a { … } select elements matching at least one selector
CSS rule precedence (cascade) determines which style applies when multiple rules match