JavaScript introductory tutorial (6) Window Window Object_Basic Knowledge

Window object in JavaScript
It is the largest object in JavaScript, and 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, 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: "Close window".
parent returns the frame page object to which the window belongs.
top returns the frame page object that occupies the top of the entire browser window.
history historical object, see below.
location address object, see below.
document document object, see below.
The Window object has the following methods:
The first method is open() to open a window.
Usage:

Copy code The code is as follows:

open(, , );

Description:
: Describes where the opened window opens. A web page. If left blank (''), no web page will be opened.
: Describes the name of the opened window (window.name). You can use built-in names such as '_top' and '_blank'. The name here is the same as the "target" attribute in "".
: 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:

Copy the code The code is as follows:

open('','_blank','width=400,height=100,menubar=no,toolbar=no,
location=no,directories=no,status=no, scrollbars=yes,resizable= yes')

Parameters of open()
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 Number
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=... Whether the window has 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 what is returned is the window object it opens. For example,
var newWindow = open('','_blank');
In this way, a new window is assigned to the "newWindow" variable, and the window can be controlled through the "newWindow" variable in the future.
close() closes an open window.
Usage:

Copy code The code is as follows:

window.close()

or

Copy code The code is as follows:

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() to remove the focus from the window and make the window 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 corresponding buttons on the window's title bar and 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); causes the window to scroll right by deltaX pixels and 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, increasing the width by deltaWidth pixels and 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 . Reading of the entire document and running of the Script will Pause until 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. Reading of documents and running of scripts will be suspended. 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 is specified, the text box will have a default value.
Window object has the following events:
window.onload; occurs when all documents are downloaded. All downloads have been completed, which means that not only the HTML files, but also 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:

Copy code The code is as follows:

function ignoreError() {
return true;
}
window.onerror = ignoreError;