Window object in JavaScript

Window object in JavaScript
It is the largest object in JavaScript. It describes a browser window. Generally, when you want to reference its properties and methods, you do not need to use the form "window.xxx", but use "xxx" directly. A frame page is also a window.

Window object has the following attributes:

name The name of the window, which is determined by the connection that opened it () or the frame page () or the open() method called by a certain window (see below). Generally we will not use this attribute.

status refers to the content displayed in the "status bar" at the bottom of the window. By assigning a value to status, the display of the status bar can be changed.

opener Usage: window.opener; returns the window object that opens this window. Note: What is returned is a window object. If the window is not opened by another window, this property returns null in Netscape and "undefined" in IE. undefined is equal to null to some extent. Note: undefined is not a JavaScript constant. If you try to use "undefined", it will really return "undefined".

self refers to the window itself, and the object it returns is exactly the same as the window object. The most commonly used is "self.close()", placed in the tag: "
parent returns the frame page object to which the window belongs .

top returns the topmost frame page object of the entire browser window.

History object, see below.

Document object, see below.

The window object has the following methods:

The first method is open() to open a window
Usage:
open(, , ). ;
Description:


: Describes which webpage the opened window opens. If left blank (), no webpage will be opened.

: Describes which webpage is opened. The name of the opened window (window.name), you can use built-in names such as _top and _blank. The name here is followed by the "
< parameter. String>: Describes the appearance of the opened window. If you only need to open a normal window, leave the string blank (). If you want to specify the appearance, write one or more parameters in the string, separated by commas.


Example: Open a 400 x 100 clean window:

open(,_blank,width=400,height=100,menubar=no,toolbar=no,

location=no,directories=no,status=no, scrollbars=yes, resizable=yes)
open() parameters


top=# The number of pixels from the top of the window to the top of the screen

left=# The number of pixels from the left end of the window to the left end of the screen

width=# The width of the window

height=# The height of the window

menubar=... Whether the window has a menu, the value is yes or no

toolbar=... Whether the window has a toolbar, the value is yes or no

location=... Window Whether there is an address bar, the value is yes or no

directories=... Whether the window has a connection area, the value is yes or no

scrollbars=... Whether the window has scroll bars, the value is yes or no

status= ... Whether the window has a status bar, the value is yes or no

resizable=... Whether the window is resized, the value is yes or no


Note: The open() method has a return value, and that is what is returned The open window object. For example,

var newWindow = open(,_blank);

In this way, a new window is assigned to the "newWindow" variable. In the future, the window can be controlled through the "newWindow" variable.

close() Close an open window.

Usage:

window.close()
or
self.close()
The main function is to close this window;
.close(): Close the specified window. Note that if the window has a status bar, after calling this method, the browser will warn: "The webpage is trying to close the window, do you want to close it?" and then wait for the user to choose whether; if there is no status bar, calling this method will directly close the window.
In addition, the Window object also has the following methods

blur() causes the focus to move away from the window and the window becomes an "inactive window".

focus() causes the window to gain focus and become the "active window". However, in Windows 98, this method can only make the window's title bar and the corresponding button on the taskbar flash, prompting the user that the window is trying to gain focus.

scrollTo() Usage: [.]scrollTo(x, y); Scroll the window so that the document scrolls from the (x, y) point counting from the upper left corner to the upper left corner of the window.

scrollBy() Usage: [.]scrollBy(deltaX, deltaY); Make the window scroll right by deltaX pixels and scroll down by deltaY pixels. A negative value scrolls in the opposite direction.

resizeTo() Usage: [.]resizeTo(width, height); Make the window resize to width pixels and height pixels.

resizeBy() Usage: [.]resizeBy(deltaWidth, deltaHeight); Make the window resize, increase the width by deltaWidth pixels, and increase the height by deltaHeight pixels. If it takes a negative value, it decreases.

alert() Usage: alert(); Pops up a dialog box containing only the "OK" button, displaying the content of , and the entire document reading and script running will be suspended. , until the user presses OK.

confirm() Usage: confirm(); Pops up a dialog box containing "OK" and "Cancel" buttons, displays the content of , and requires the user to make a choice, the entire document Reading and script execution will be paused. Returns a true value if the user pressed OK and a false value if Cancel was pressed.

prompt() Usage: prompt([, ]); Pops up a dialog box containing "Confirm", "Cancel" and a text box, displaying The content requires the user to enter some data in the text box, and the reading of the entire document and the running of the script will be suspended. If the user presses "Confirm", the existing content in the text box is returned. If the user presses "Cancel", a null value is returned. If is specified, the text box will have a default value.

Window object has the following events:
window. HTML file, and all included images, plug-ins, controls, applets, etc. have been downloaded. This event is a window event, but when specifying the event handler in HTML, we write it in the tag.
window.onunload; occurs when the user exits the document (or closes the window, or goes to another page). Like onload, if you want to write it in HTML, write it in the tag.

window.onresize; occurs when the window is resized.

window.onblur; occurs when the window loses focus.

window.onfocus; occurs when the window gets focus.

window.onerror; occurs when an error occurs. Its event handler is usually called an "Error Handler" and is used to handle errors. As mentioned above, to ignore all errors, use:
function ignoreError() {
return true;
}
window.onerror = ignoreError;