A little understanding of javascript Summary of "javascript advanced programming" Reading Notes _ javascript skills

Javascript is a scripting language designed for interaction with Web pages. It is constructed by the following three departments l ECMAScript, defined by a ECMA-262, defining the rules and conventions of the javascript language, it is like the rules, specifications, and conventions specified for starting a game.
L DOM: provides methods and interfaces for accessing and operating webpage content
L BOM, which provides methods and interfaces for interacting with browsers

ECMA-262 specifies the following:
L syntax
L type
L keywords
L reserved words
L Operator
L object
ECMAScript is a programming language description of all aspects of the content specified by this standard. javascript implements and extends the content specified by ECMAScript.

BOM is used to access the browser, including the following features:

L Window object: (1) Window relationship and framework; (2) Window position; (3) Window size; (4) Navigation and Window opening; (5) intermittent call and timed call; (6) system dialog box (7) location object;
L Location object: provides information about the documents loaded in the current window of the fish (1) query string parameters; (2) Location operations;
L Navigator object: it is used to detect the browser type of the displayed web page. Different browsers have different implementations. The main functions are as follows: (1) detection plug-in; (2) Registration Handler
L Screen Object: indicates the client's capabilities, including the height and width of the display displayed in the browser window.
L History object: stores the historical records of the user's Internet access, which is the attribute of the window object. Therefore, each browser window, each window, and each frame have its own history object.


DOM: used to operate on page tags. It depicts an html file as a structure constructed by multiple layers of nodes, including the following content:
L Document type:
L Element type: provides access to Element label names, subnodes, and features.
L Text type: plain Text content, which can contain Html characters after escaping, but not html code
L Comment type: Comment in Dom
L CDATASection type: Only applicable to xml documents
L DocumentType
L DocumentFragment type
L Attr type: Indicates node features

Event: the implementation of interaction between javascript and html. When a document or browser window experiences a specific interaction, it is an event. Its implementation adopts the observer mode and supports loose coupling between page behavior and page appearance.
There are several types of events:
L UI events
L mouse events
L Keyboard Events
L HTML events
L change event: triggered when the underlying Dom structure changes.