Thứ Ba, 26 tháng 8, 2014
JavaScript: Window Location
The window.location object can be written without the window prefix.
Some examples:
- location.href returns the href (URL) of the current page
- location.hostname returns the domain name of the web host
- location.pathname returns the path and filename of the current page
- location.protocol returns the web protocol used (http:// or https://)
- location.assign loads a new document
Do Not Declare String, Number, and Boolean as Objects!
When a JavaScript variable is declared with the keyword "new", the variable is created as an object:
var x = new String(); // Declares x as a String object
var y = new Number(); // Declares y as a Number object
var z = new Boolean(); // Declares z as a Boolean object
var y = new Number(); // Declares y as a Number object
var z = new Boolean(); // Declares z as a Boolean object
JavaScript: Window Screen
The window.screen object contains information about the user's screen.
Window Screen
The window.screen object can be written without the window prefix.
Properties:
- screen.width
- screen.height
- screen.availWidth
- screen.availHeight
- screen.colorDepth
- screen.pixelDepth
Window Screen Width
The screen.width property returns the width of the visitor's screen in pixels.
Example
Display the width of the screen in pixels:
"ScreenWidth: " + screen.width
Result will be:
Screen Width: 1024
Try it Yourself »
Window Screen Height
The screen.height property returns the height of the visitor's screen in pixels.
Example
Display the height of the screen in pixels:
"Screen Height: " + screen.height
Result will be:
Screen Height: 768
Try it Yourself »
Window Screen Available Width
The screen.availWidth property returns the width of the visitor's screen, in pixels, minus interface features like the Windows Taskbar.
Example
Display the available width of the screen in pixels:
"Available Screen Width: " + screen.availWidth
Result will be:
Available Screen Width: 1024
Try it Yourself »
Window Screen Available Height
The screen.availHeight property returns the height of the visitor's screen, in pixels, minus interface features like the Windows Taskbar.
Example
Display the available height of the screen in pixels:
"Available Screen Height: " + screen.availHeight
Result will be:
Available Screen Height: 728
Try it Yourself »
Window Screen Color Depth
The screen.colorDepth property returns the number of bits used to display one color.
All modern computers use 24 or 32 bits hardware to display 16,777,216 different colors ("True Colors").
Older computers used 16 bits, which gives a maximum of 65,536 different colors ("High Colors")
Very old computers, and old cell phones used 8 bits ("VGA colors").
Example
Display the color depth of the screen in bits:
"Screen Color Depth: " + screen.colorDepth
Result will be:
Screen Color Depth: 24
Try it Yourself »
Some computers report 32. Most computers report 24. Both display "True Colors" (16,777,216 different colors). |
Window Screen Pixel Depth
The screen.pixelDepth property returns the pixel depth of the screen.
Example
Display the pixel depth of the screen in bits:
"Screen Pixel Depth: " + screen.pixelDepth
Result will be:
Screen Pixel Depth: 24
Try it Yourself »
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