The comparison operator '!==' checks for inequality while also considering type coercion. It returns true if the values are not equal or if their types are not the same. For example, 5 !== "5" would evaluate to true because the number 5 is not equal to the string "5."

JavaScript implements inheritance through a prototype chain and object delegation. Each object has a prototype object, and if a property or method is not found on the object itself, it's looked up on the prototype chain. This mechanism allows objects to inherit properties and methods from their prototypes, facilitating code reuse and object-oriented programming in JavaScript. Classes and interfaces are not directly related to inheritance in JavaScript.

JavaScript was first implemented in Netscape Navigator. Brendan Eich developed it in 1995 while working at Netscape Communications. This move by Netscape added a significant interactive element to the web and contributed to the rapid adoption of JavaScript.

The for...of loop handles string iteration by iterating over each character in the string. It treats the string as an iterable object where each character is an element, allowing you to loop through and process individual characters in a string efficiently.

The default case in a switch statement serves as a fallback option. If none of the other cases match the expression's value, the code in the default case block is executed. This ensures that there is always a valid path in the switch.

Arrow functions are not recommended for use as event handlers in the DOM. This is because the value of "this" in an arrow function is not determined by the event but instead retains the value from its enclosing lexical context, which may not be what you expect in an event handler. Traditional functions are usually preferred for event handlers.

If no case matches in a switch statement and there is no default case, the control is passed to the next statement after the switch. This behavior is important to understand because it determines what happens when none of the cases match the expression value.

In JavaScript, the "this" keyword typically refers to the parent object, which is the object that calls the function. It allows you to access and manipulate the properties and methods of that object within the function. This behavior is crucial for object-oriented programming in JavaScript.

In JavaScript, the Symbol data type can be used to create unique identifiers. Symbols are often used as object property keys when you need to ensure that the key is unique and not accidentally overwritten. They are not used to create objects, functions, or private variables.

In JavaScript, a callback function is a function that can be passed as an argument to another function. Callback functions can accept up to three arguments: the value of the element, the index of the element, and the array object being traversed. They are commonly used in asynchronous programming and array methods.