JavaScript study notes built-in objects_basic knowledge

JS Window

Window object: http://www.w3school.com.cn/js/js_window.asp

All browsers support the window object. It represents the browser window.

All JavaScript global objects, functions and variables automatically become members of the window object.

Properties and methods format of window object:

　[window.]Property

　[window.]Method (parameter)

Even the document of HTML DOM is one of the attributes of the window object:

window.document.getElementById("header");
Same as this:

document.getElementById("header");

JS Screen

Screen object: http://www.w3school.com.cn/js/js_window_screen.asp

The screen object mainly describes the display and color properties of the screen.

Properties of the screen object:

Format: screen.Attribute

Screen.availWidth - Available screen width

Screen.availHeight - available screen height

Measured in pixels, minus interface features such as the window taskbar.

JS Location

Location object: http://www.w3school.com.cn/js/js_window_location.asp

The location object is used to represent the URL information of a specific window.

The window.location object can be written without the window prefix.

Some examples:

Location.hostname returns the domain name of the web host

Location.pathname returns the path and file name of the current page

Location.port returns the port of the web host (80 or 443)

Location.protocol returns the web protocol used (http:// or https://)

　The location.href property returns the URL of the current page.

The location.assign() method loads a new document.

JS History

Historical objects: http://www.w3school.com.cn/js/js_window_history.asp

The history object is used to store the list of URLs recently visited by the client.

In order to protect user privacy, JavaScript’s method of accessing this object is restricted.

Some methods:

History.back() - Same as clicking the back button in the browser

History.forward() - Same as clicking the button forward in the browser

File Object

File object: Represents the current HTML object, which is composed of tag group. A file object will be automatically created for each HTML file.

Format:

Document.Attribute

Document.Method (parameter)

Link object

The links in the web page will be automatically regarded as link objects, and in order, they are represented as document.links[0], document.links[1]...

Define the format of the link object:

String.link(property)

Form Object
As a sub-object of the file object, Javascript’s runtime engine automatically creates a form object for each form.

Format:

　document.forms[index].Properties

　document.forms[index].Method (parameter)

Document.Form name.Attribute

Document.Form name.Method (parameter)