#Dom first how to
#Dom first update
#Dom first code
#Dom first series

nodeType 1 // -> ELEMENT_NODE > var text = document. createElement ( ' div ' ) undefined > div. Let’s query the node type of a few more DOM objects. To find out which node type that number represents, we need to reference the following table.

#Dom first how to

Please read this nice tutorial from WickedlySmart for learning how to open the console on various browsers. Opening browser console Instructions for opening the browser console depends on which browser you’re using.

#Dom first code

Open browser console from the counter app page located at and enter the code after the > prompt below into the console. We can actually query the node type from a browser. The official DOM specification contains many more types of nodes. Similarly, the comments and plain text can be represented using the comment and text nodes respectively. The element attributes such as id and class can be represented using the attribute nodes. Nodes that can be used to specify an HTML tag are called elements. The browser then takes a sequence of tokens from the tokenization stage, creates respective DOM objects, and adds them to the tree as the document node’s children. When the DOM tree creation process begins, the document node is the first one to be created. It is a special type of node that represents the entire HTML document. For example, the root node in the DOM tree is known as document. We can be specific and call each node with a different name based on what type of object it represents. The objects in the DOM tree are often referred to as nodes in HTML parlance. The mapping is very close because the browser builds a DOM tree from tokens extracted from the original HTML code as shown below. The DOM objects tend to have almost one-to-one mapping to the HTML markup as shown in the figure below. With access to the object representation of each element in the HTML page, we can now add, change, and remove HTML elements and attributes change the CSS styles react to existing events or create new events through JavaScript. A tree is a data structure that simulates the hierarchical relationship between objects.

#Dom first update

To make this update easier, the browser creates the DOM tree for the page. For example, when the user clicks the + button in the counter app we built earlier, we need to increment the count. That way, programming languages can connect to the page.” - Mozilla Developer NetworkĪfter an HTML page is loaded, we often need to make changes to it based on various events generated either by the user or some other source. The DOM represents the document as nodes and objects. It represents the page so that programs can change the document structure, style, and content. Document Object Model “The Document Object Model (DOM) is a programming interface for HTML and XML documents. The next step is to create the Document Object Model (DOM) tree using these tokens.

#Dom first series

The figure below shows all the tokens present in our code.ĭuring the tokenization phase, the browser processed our code, which started as a stream of text characters, into a series of tokens. The browser continues to step through the characters in our code, converting them into more tokens. The series of characters between are converted into the first start tag token called html. The first character it encounters is, which marks the end of a start tag token. The first thing a browser does is step through the characters one at a time starting from the beginning.

To keep things simple, only a portion of the code is shown here. The figure below shows how the above code appears to a browser - a series of text characters.

Browsers use a process called tokenization or lexical analysis to break a chunk of HTML code into individual tokens. For example, the vocabulary of the English language consists of all the words that appear in a dictionary. Collectively, they represent the entire vocabulary of that language. Tokens are the building blocks of a language. The first thing a browser does when it encounters the above code is create HTML tokens. Let’s look at how the following HTML code we saw earlier in the Model View Update - Part 1 section gets rendered. When a browser is given some HTML code, it takes that code through a series of transformations before the UI elements are displayed on a screen. First, let’s understand how browsers render HTML in general. In this section, we’ll learn how this package works. The Elm runtime uses a package called elm/virtual-dom to render HTML on a screen.