Understanding The Problem Domain Is The Hardest Part Of Programming
because you can’t really see what you are trying to build very clearly.
By creating a familiar problem domain, I found that both the tasks of me teaching a new technology and the viewer learning that technology were much easier, because it is very difficult to learn more than one thing at once.
Objects group together a set of variables and functions to create a modelof a something you would recognize from the real world. In an object,variables and functions take on new names.
- IN AN OBJECT: VARIABLES BECOME KNOWN AS PROPERTIES
- IN AN OBJECT: FUNCTIONS BECOME KNOWN AS METHODS
The Document Object Model (DOM) specifies how browsers should create a model of an HTML page and how JavaScript can access and update the contents of a web page while it is in the browser window.
The DOM is neither part of HTML, not part of JavaScript; it is a separate set of rules. It is implemented by all major browser makers, and covers two primary areas:
- MAKING A MODEL OF THE HTML PAGE
- ACCESSING AND CHANGING THE HTML PAGE
DOM tree have two sectio
-
ATTRIBUTE NODES : The opening tags of HTML elements can carry attributes and these are represented by attribute nodes in the DOM tree.
-
TEXT NODES : Once you have accessed an element node, you can then reach the text within that element. This is stored in its own text node.
Accessing and updating the DOM tree involves two steps:
-
Locate the node that represents the element you want to work with.
-
Use its text content, child elements, and attributes.
DOM queries may return one element, or they may return a Nodelist, which is a collection of nodes.
- getElementByTagName
- getElementByTagName.html
- getElementByClassName
