An HTML attribute adds information or behavior to an element. It appears in the start tag and usually has a name and value, such as charset="utf-8"; some attributes, such as required, need no value. section 3.2.2 section 3.2.3
Angular also applies features through HTML attributes. Attribute values may be evaluated as JavaScript expressions; quote a string inside the attribute value when you want Angular to treat it as a literal. section 3.2.4 section 9.4.4
Expression versus literal
In [ngSwitch]="item.complete", Angular reads the complete property from item. In [ngSwitch]="'Apples'", the inner quotes make Apples a literal string. section 3.2.4
... <meta charset="utf-8" /> ...
A meta element shows a name-value attribute in its start tag. section 3.2.2
An object property is related terminology, but not the same thing as an HTML attribute: JavaScript objects have named properties whose values can be data or functions. section 4.4 section 4.6
