What is JavaScript? A quick intro for programmers
What is JavaScript?
JavaScript is a client-side interpreted language made up of three parts:
- The Core based on the ECMAScript standard.
- The BOM which stands for Browser Object Model
- The DOM which stands for Domain Object Model
Now for some more info about the parts……
What the heck it ECMAScript? (Part of the JS Core…duh!)
ECMAScript is a standard for scripting languages that JavaScript implements. The first ECMAScript specification document came out in June of 1997, and it has undergone 10 revisions so far.
BOM and DOM… Are those explosions?
BOM is the Browser Object Model. It allows access to objects in the browser like history, form elements, and the URL. Here are all the broad categories with an example for each. More detailed info can be found here:
- Navigator- Cookies and info about the users browser
- History- Info about URL’s
- Screen- The visitors screen size, and color depth
- Location- Redirects and current page url parsing
- Document- This ones’ a doozy! Check out the section below
DOM (Domain Object Model) A.K.A the Document object
Why does it get its own section? Two reasons:
- Because it has its own standardized specification- meaning that it will work across browsers much more consistently than the browser object.
- Because the document object has a lot more functionality than the other models.
The document object is so commonly used that many people don’t even realize the Browser Object Model exists! In simple terms it is an API for HTML/XML. When used inside something like a browser it allows access to stuff on the web page itself. For example, to get the header of the page you could write something like this:
document.getElementById("header");Want more info? Check out these great links:
