Head First JavaScript Programming Quotes

“Note that the JSON format doesn’t work with methods (so you can’t include, say, a bark method in your JSON string), but it does work with all the primitive types, as well as objects and arrays.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“You can use arguments to create a function that accepts a variable number of arguments, or create a function that does different things depending on the number of arguments passed to it. Let’s”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“An object named arguments is available in every function when that function is called. You”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“When you declare any kind of global variable or define a global function, it is stored as a property in the window object. So”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“That’s because the default prototype for any instance you create (assuming you don’t change it) is Object.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“The hasOwnProperty method returns true if a property is defined in an object instance. If it’s not, but you can access that property, then you can assume the property must be defined in the object’s prototype.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“If you change any property in the prototype, it affects all the objects that inherit from that prototype, unless that object has overridden that property.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“You see, now that we have a prototype, if we add any methods to that prototype, even after we’ve already created dog objects, all dogs inheriting from the prototype immediately and automatically get this new behavior.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“When you call an object’s method, this is set to the object whose method was called. If the method is not found in that object, and is found in the prototype, that doesn’t change the value of this. this always refers to the original object — that is, the object whose method was called — even if the method is in the prototype. So,”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“the constructor always has a prototype property. More”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“in JavaScript just about everything is an object underneath, even”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“Here’s the short story: functions are objects in JavaScript. In”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“JavaScript doesn’t have a classical object-oriented model, where you create objects from classes. In fact, JavaScript doesn’t have classes at all. In JavaScript, objects inherit behavior from other objects, which we call prototypal inheritance, or inheritance based on prototypes.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“JavaScript has a very powerful object model, but one that is a bit different than the status quo object-oriented language. Rather than the typical class-based object-oriented system, JavaScript instead opts for a more powerful prototype model, where objects can inherit and extend the behavior of other objects. What”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“An object literal is an instance of Object. Think”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“Math is not a constructor, or even a function. It’s an object. As you know, Math is a built-in object that you can use to do things like get the value of pi (with Math.PI) or generate a random number (with Math.random). Think of Math as just like an object literal that has a bunch of useful properties and methods in it, built-in for you to use whenever you write JavaScript code. It just happens to have a capital first letter to let you know that it’s built-in to JavaScript.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“Yes, a car is still a car, even if you change it later.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“using constructors still doesn’t prevent us from changing an object into something else later, because”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“As it turns out, one of the things the new operator does behind the scenes when the object is created is to store information that allows it to determine, at any time, the constructor that created the object. And”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“methods in objects are properties too. They just happen to have a function assigned to them.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“Closures are often used to capture state for event handlers.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“Closures are a function along with a referencing environment.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“Lexical scope means that we can determine the scope of a variable by reading our code.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“One thing that often misleads people learning closures is that they think the environment in the closure must have a copy of all the variables and their values. It doesn’t. In”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“Now, when we have an environment that has a value for each of the free variables, we say that we’ve closed the function. And, when we take the function and the environment together, we say we have a closure.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“By lexical scope we mean that JavaScript’s rules for scoping are based purely on the structure of your code (not on some dynamic runtime properties). This means you can determine where a variable is defined by simply examining your code’s structure. Also”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“We take donations in chocolate, pizza or bitcoins.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“An expression is anything that evaluates to a value. 3+4”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“Now when we use the function keyword this way — that is, within a statement, like an assignment statement — we call this a function expression. Notice”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide

“Well, say you write a handler and it requires a lot of computation — that is, something that takes a long time to compute. As long as your handler is chugging along computing, I’m sitting around waiting until it’s done. Only then can I continue with the queue.”
― Eric Freeman, Head First JavaScript Programming: A Brain-Friendly Guide