JavaScript window width and height, mouse position, scroll height (detailed analysis)_Basic knowledge

Width of the visible area of ​​the web page: document.body.clientWidth
Height of the visible area of ​​the web page: document.body.clientHeight
Width of the visible area of ​​the web page: document.body.offsetWidth (including the width of the edges)
Height of the visible area of ​​the webpage: document.body.offsetHeight (including the width of the edge)
Full text width of the webpage body: document.body.scrollWidth
Height of the full text of the webpage body: document.body.scrollHeight
The webpage is scrolled The height: document.body.scrollTop
The left side of the webpage being scrolled: document.body.scrollLeft
The top part of the webpage body: window.screenTop
The left side of the webpage body part: window.screenLeft
Screen resolution The height of the screen resolution: window.screen.height
The width of the screen resolution: window.screen.width
Screen available work area height: window.screen.availHeight
Screen available work area width: window.screen. availWidth

HTML precise positioning: scrollLeft, scrollWidth, clientWidth, offsetWidth
scrollHeight: Get the scroll height of the object.
scrollLeft: Sets or gets the distance between the left edge of the object and the leftmost end of the currently visible content in the window
scrollTop: Sets or gets the distance between the topmost edge of the object and the topmost end of the visible content in the window
scrollWidth: Get the scroll width of the object
offsetHeight: Get the height of the object relative to the layout or the parent coordinate specified by the offsetParent property
offsetLeft: Get the height of the object relative to the layout or the parent coordinate specified by the offsetParent property Calculate the left position
offsetTop: Get the calculated top position of the object relative to the layout or the parent coordinate specified by the offsetTop attribute
event.clientX The horizontal coordinate relative to the document
event.clientY The vertical coordinate relative to the document
event.offsetX is the horizontal coordinate relative to the container
event.offsetY is the vertical coordinate relative to the container
document.documentElement.scrollTop is the value of vertical scrolling
event.clientX document.documentElement.scrollTop is relative to the horizontal position of the document The amount of vertical scrolling of coordinates

The differences between IE and FireFox are as follows:

IE6.0, FF1.06:

clientWidth = width padding

clientHeight = height padding

offsetWidth = width padding border

offsetHeight = height padding border

IE5.0/5.5:
clientWidth = width - border

clientHeight = height - border

offsetWidth = width

offsetHeight = height

(It needs to be mentioned: the margin attribute in CSS has nothing to do with clientWidth, offsetWidth, clientHeight, and offsetHeight)

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The code in this section mainly uses some properties of the Document object regarding the window. The main functions and usage of these properties are as follows.

To get the size of the window, different properties and methods need to be used for different browsers:

To detect the real size of the window, you need to use the properties of Window under Netscape;

Under IE, you need to go deep inside the Document to detect the body;

In the DOM environment, if you want to get the size of the window, you need to pay attention to the size of the root element, not the element.

The innerWidth property of the Window object contains the inner width of the current window.

The innerHeight property of the Window object contains the inner height of the current window.

The body attribute of the Document object corresponds to the tag of the HTML document.

The documentElement property of the Document object represents the root node of the HTML document.

document.body.clientHeight represents the current height of the window where the HTML document is located.

document.body.clientWidth represents the current width of the window where the HTML document is located.

Implementation code:

Copy code The code is as follows:

Please resize the browser window

The actual height of the browser window:

The actual width of the browser window:

Source program interpretation

(1) The program first creates a form containing two text boxes to display the current width and height of the window, and their values ​​will change as the window size changes.

(2) In the subsequent JavaScript code, two variables winWidth and winHeight are first defined to save the height and width values ​​of the window.

(3) Then, in the function findDimensions (), use window.innerHeight and window.innerWidth to get the height and width of the window, and save them in the two aforementioned variables.

(4) Then detect the body by going deep into the Document, obtain the window size, and store it in the two variables mentioned above.

(5) At the end of the function, by accessing the form elements by name, the results are output to two text boxes.

(6) At the end of the JavaScript code, complete the entire operation by calling the findDimensions () function.