Head First HTML5 Programming Quotes

“You can’t insert new ”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“Web Workers have a global function named importScripts that you can use to import one or more JavaScript files into your worker. To”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“Yes, workers can access localStorage and make XMLHttpRequests.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“when you send an object the worker gets a copy of it. Any changes the worker makes will not affect the object in your main page. The worker is executing in a different environment than your main page, so you have no access to objects there. The same is true of objects the worker sends you: you get a copy of them.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“You can’t send functions:”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“JavaScript: When an event occurs, like the ones you’ve mentioned, that event is added to a queue. I don’t even look at it until I’ve finished whatever I’m working on. That way I do everything correctly and safely and efficiently.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“When I’m loading a page from my computer, like we are in these exercises, what is my origin? A: A: Good question. In that case your origin is known as the “Local Files” origin, which”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“When you pass zero to setTimeout, you’re asking JavaScript to run your timeout handler as soon as it possibly can — and this leads to your handler running as frequently as it possibly can.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“We haven’t done much writing code, but we are reading and understanding code, and that can be just as good. So”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“So, we recommend specifying the width and height in the tag attributes, and not setting those properties in CSS unless you really mean to scale the canvas.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“Well, it’s a browser policy, and it says you can’t retrieve data from a domain that is different from the domain the page itself was served from. Say”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“Also notice that longitude West and latitude South are represented by negative values.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“You’ve probably seen latitude and longitude specfied in both degrees/minutes/seconds, such as (47°38’34’’, 122°32’32’’), and in decimal values, such as (47.64, -122.54). With the Geolocation API we always use decimal values. If”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“If you assign a new variable without using the var keyword, that variable will be global, even if you are first assigning it in a function.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“When you link to multiple JavaScript files from your page, all the global variables are defined in the same global space.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“Window is the global object. It may seem a little weird, but the window object acts as your global environment, so the names of any properties or methods from window are resolved even if you don’t prepend them with window. In addition, any global variables you define are also put into the window namespace, so you can reference them as window.myvariable.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“when you assign a value to a variable name that hasn’t been previously declared, it is treated as a new, global variable. So be careful, if you do this within a function you are creating a global variable. Note”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“If a variable is declared outside a function, it’s GLOBAL. If it’s declared inside a function, it’s LOCAL.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“A function without a return statement returns undefined.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript

“When you pass a primitive value it is copied into the parameter. We call this “passing by value.” So if you change the value of the parameter in your function body it has no affect on our original argument’s value. The exception to this is passing an array or object, and we’ll get to that in a bit.”
― Eric Freeman, Head First HTML5 Programming: Building Web Apps with JavaScript