Unit04:bom Overview, Window object, window common sub-object-1

Review:

1. Form object:

How to find: document.forms[serial number |name]

How to find the elements of data acquisition:

document.forms[ordinal |name].elements[serial number |name]

To get or lose focus on an element: Elem.focus ()

Elem.blur ()

Get/Lose Focus event: onfocus onblur

Get the element that is currently getting focus: document.activeelement

Event: OnSubmit is automatically triggered before the form is formally submitted

Perform validation on the entire form

Form.onsubmit=function () {

As long as any one of the validations does not pass,

just * Cancel Event *: 2 steps:

1. Get the Event object e:

var e=window.event| | Arguments[0];

if (E.preventdefault) {

E.preventdefault ()//dom

}else{

E.returnvalue=false//IE8

}

Form submission: 2 kinds:

-Direct Click on the Submit button;

-If any element in the current form receives focus, it can be automatically submitted by pressing ENTER;

As long as the automatic form submission, the onsubmit will be triggered first, can be verified

"BOM"

BOM: The object that operates the browser window;

1.window objects: 2 characters;

-Acts as a global object;

-Superiors of all BOM objects;

Properties: (can only be obtained, cannot be set)

-Innerheight; height of document display area

-Innerwidth;

-Outerheight; window height;

-Outerwidth

-pageYOffset; The distance from the upper-left corner of the document to the upper-left corner of the document display;

-Pagexoffset;

Open Connection: 4 species;

-Open a new connection in the current window and back up;

Html:target= "_self";

Js:[window.] Open ("url", "_self")

-Open a new connection in the current window, prohibit backward;

Js:location.replace ("New url");

-Opens in new window, can be opened repeatedly

Html:target= "_blank";

Js:[window.] Open ("url", "_blank")

-Open in New window, cannot be opened repeatedly

Target--> the name of the target window

_self: Automatically get the current window name

_blank: Create a new window, randomly generate a duplicate name

* Window name: The same window name in memory can only open one, after open, will replace the first open;

html:target= "Custom window name";

Js:[window.] Open ("url", "Custom window name");

2. Window size and positioning:

Size:

1. Window.innerheight/width: Document display area width height

Outerheight/width: Width of the entire window

2. Screen.height/width: Desktop full resolution width high

Screen.availheight/availwidth: Remove the width of the remaining resolution after the taskbar

3. Sizing: Window.resizeto (width,height)

Adjusted to

Resizeby (variable width, height of change)

Position:

1. Upper left corner x coordinate: window.screenleft| | Window.screenx;

Y coordinate: window.screentop| | Window.screeny;

2. Move the window to the specified coordinates: window.moveto (x, y)

3. When an event occurs, the mouse is relative to the entire screen's coordinates:

Event.screenx|screeny

3. Timer: Animation; * * * [4_1.html]

Timer: Allow the browser to perform the same task repeatedly at specified intervals

2 Kinds:

Recurring timer: Lets the browser perform the same task repeatedly at a specified time interval, and executes repeatedly if not manually stopped

Disposable Timer: Let the browser wait for a period of time, perform a task, and automatically stop.

At the end of the one-time timer, reboot a disposable timer

Recommendation: Try to use one-time timers instead of periodic timers

How to use: Periodic and disposable usage exactly the same

Periodicity: 3 things:

1. The task to be performed for each step of the animation (function object)

function Step () {

What to do every step of the way

}

2. Put one-step task into the timer and call repeatedly

Timer=setinterval (step, interval of milliseconds)

3. You must use global variables to temporarily store the timer's number

Clearinterval (timer)

Disposable: 3 Things

1. The task to be performed for each step of the animation (function object)

function Step () {

What to do every step of the way

/* Determine if it is necessary to continue to start the next timer according to the conditions */}

2. Put one-step task into the timer and call repeatedly

Timer=settimeout (step, interval milliseconds | Number of milliseconds to wait)

3. You must use global variables to temporarily store the timer's number

Cleartimeout (timer)

Stop the timer that is waiting

Unit04:bom Overview, Window object, window common sub-object-1