Javascript DOM, Bom

 Document Object Model

DOM - это всего лишь набор объектов и методов в них, для работы с содержимым html-страниц. Это своеобразная прослойка между JS-кодом и содержимым html-страницы

 Document Object Model

With the HTML DOM, JavaScript can access and change all the elements of an HTML document.

With the object model, JavaScript gets all the power it needs to create dynamic HTML:

  • JavaScript can change all the HTML elements in the page
  • JavaScript can change all the HTML attributes in the page
  • JavaScript can change all the CSS styles in the page
  • JavaScript can remove existing HTML elements and attributes
  • JavaScript can add new HTML elements and attributes
  • JavaScript can react to all existing HTML events in the page
  • JavaScript can create new HTML events in the page

DOM Programming Interface

  • The HTML DOM can be accessed with JavaScript (and with other programming languages).
  • In the DOM, all HTML elements are defined as objects.
  • The programming interface is the properties and methods of each object.
  • A property is a value that you can get or set (like changing the content of an HTML element).
  • A method is an action you can do (like add or deleting an HTML element).

HTML DOM Document Object

The HTML DOM document object is the owner of all other objects in your web page.

The document object represents your web page.

If you want to access any element in an HTML page, you always start with accessing the document object.

Finding Elements

Method Description
document.getElementById(id) Find an element by element id
document.getElementsByTagName(name) Find elements by tag name
document.getElementsByClassName(name) Find elements by class name
document.querySelector(selectors); Returns the first element within the document using CSS like selector
document.querySelectorAll(selectors); Returns a list of the elements within the document using CSS like selector

Changing HTML Elements

Method Description
element.innerHTML =   new html content Change the inner HTML of an element
element.setAttribute (attribute, value)(getAttribute, hasAttribute) Change the attribute value of an HTML element
element.style. property = new style Change the style of an HTML element

Adding and Deleting Elements

Method Description
document.createElement(element) Create an HTML element
document.removeChild(element) Remove an HTML element
document.appendChild(element) Add an HTML element
document.replaceChild(newChild, oldChild) Replace an HTML element
document.write(text) Write into the HTML output stream
document.insertBefore(newEl, el); Insert an element before second argument ekement

properties and metods oF Node

childNodes все прямые потомки узла 
firstChild   первый прямой потомок узла
 lastChild    последний прямой потомок узла
nextSibling  соседний узел, стоящий за текущим
previousSibling  соседний узел, стоящий перед текущим
nodeType тип узла (текст, элемент, комментарий и т.д.)
parentNode  родительский узел

Text

Forms

jquery

◦ Window ◦   Document ◦  Screen ◦  Navigator

◦  Location ◦  History

BOM objects

JavaScript Window

The Browser Object Model (BOM) allows JavaScript to "talk to" the browser.

  • The window object is supported by all browsers. It represents the browser's window.
  • All global JavaScript objects, functions, and variables automatically become members of the window object.
  • Global variables are properties of the window object.
  • Global functions are methods of the window object.
  • Even the document object (of the HTML DOM) is a property of the window object:
var newwin = window.open();
if (newwin.closed) {
 document.getElementById("mes").innerHTML = "Окно newwin было закрыто.";
} else{
 document.getElementById("mes").innerHTML = "Окно newwin открыто в данный момент.";
}

Adding Events Handlers

Method Description
document.getElementById(id).onclick = function(){code} Adding event handler code to an onclick event
document.getElementById(id).addEventListener('click', handler) Adding event listener
document.getElementById(id).removeEventListener('click', handler) Removing event listener by the reference

Home work

https://learn.javascript.ru/document Документ и объекты страницы

Class work

Use only JavaScript for layout and adding styles

Task 1

Create such article block


The layout is changing according to window size

Task 2

Create Dropdown top menu 

Hover

Click

Hover menu item

Use only JavaScript events

THANKS FOR YOUR ATTENTION

JAVASCRIPT DOM, BOM

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