
JavaScript手册
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	索引

document

Contains information about the current document, and provides methods for displaying HTML output to the user.

客户端对象
实现版本 Navigator 2.0
Navigator 3.0: 添加了 onBlur and onFocus语法; 添加了 applets, domain, embeds, forms, formName, images, and plugins properties.
Navigator 4.0: 添加了 layers 属性; 添加了 captureEvents, getSelection, handleEvent, releaseEvents, and routeEvent 方法s.

创建源

The HTML BODY tag. The JavaScript runtime engine creates a document object for each HTML page. Each Window object has a document property whose value is a document object.

To define a document object, use standard HTML语法 for the BODY tag with the addition of JavaScript event handlers.

事件句柄

The onBlur, onFocus, onLoad, and onUnload event handlers are specified in the BODY tag but are actually event handlers for the Window object. The following are event handlers for the document object.

onClick

onDblClick

onKeyDown

onKeyPress

onKeyUp

onMouseDown

onMouseUp

描述

An HTML document consists of HEAD and BODY tags. The HEAD tag includes information on the document's title and base (the absolute URL base to be used for relative URL links in the document). The BODY tag encloses the body of a document, which is defined by the current URL. The entire body of the document (all other HTML elements for the document) goes within the BODY tag.

You can load a new document by setting the Window.location property.

You can clear the document pane (and remove the text, form elements, and so on so they do not redisplay) with these statements:

document.close();
document.open();
document.write(); You can omit the document.open call if you are writing text or HTML, since write does an implicit open of that MIME type if the document stream is closed.

You can refer to the anchors, forms, and links of a document by using the anchors, forms, and links arrays. These arrays contain an entry for each anchor, form, or link in a document and are properties of the document object.

Do not use location as a property of the document object; use the document.URL property instead. The document.location property, which is a synonym for document.URL, will be removed in a future release.

属性概览

方法概览

captureEvents Sets the document to capture all events of the specified type.
close Closes an output stream and forces data to display.
getSelection Returns a string containing the text of the current selection.
handleEvent 调用指定事件的控制句柄。
open Opens a stream to collect the output of write or writeln 方法s.
releaseEvents Sets the window or document to release captured events of the specified type, sending the event to objects further along the event hierarchy.
routeEvent Passes a captured event along the normal event hierarchy.
write Writes one or more HTML expressions to a document in the specified window.
writeln Writes one or more HTML expressions to a document in the specified window and follows them with a newline character.

示例

The following example creates two frames, each with one document. The document in the first frame contains links to anchors in the document of the second frame. Each document defines its colors.

doc0.html, which defines the frames, contains the following code:

<HTML>
<HEAD>
<TITLE>Document object example</TITLE>
</HEAD>
<FRAMESET COLS="30%,70%">
<FRAME SRC="doc1.html" NAME="frame1">
<FRAME SRC="doc2.html" NAME="frame2">
</FRAMESET>
</HTML> doc1.html, which defines the content for the first frame, contains the following code:

<HTML>
<SCRIPT>
</SCRIPT>
<BODY
   BGCOLOR="antiquewhite"
   TEXT="darkviolet"
   LINK="fuchsia"
   ALINK="forestgreen"
   VLINK="navy">
<P><B>Some links</B>
<LI><A HREF="doc2.html#numbers" TARGET="frame2">Numbers</A>
<LI><A HREF="doc2.html#colors" TARGET="frame2">Colors</A>
<LI><A HREF="doc2.html#musicTypes" TARGET="frame2">Music types</A>
<LI><A HREF="doc2.html#countries" TARGET="frame2">Countries</A>
</BODY>
</HTML> doc2.html, which defines the content for the second frame, contains the following code:

<HTML>
<SCRIPT>
</SCRIPT>
<BODY
BGCOLOR="oldlace" onLoad="alert('Hello, World.')"
TEXT="navy">
<P><A NAME="numbers"><B>Some numbers</B></A>
<UL><LI>one
<LI>two
<LI>three
<LI>four</UL>
<P><A NAME="colors"><B>Some colors</B></A>
<UL><LI>red
<LI>orange
<LI>yellow
<LI>green</UL>
<P><A NAME="musicTypes"><B>Some music types</B></A>
<UL><LI>R&B
<LI>Jazz
<LI>Soul
<LI>Reggae</UL>
<P><A NAME="countries"><B>Some countries</B></A>
<UL><LI>Afghanistan
<LI>Brazil
<LI>Canada
<LI>Finland</UL>
</BODY>
</HTML>

alinkColor

A string specifying the color of an active link (after mouse-button down, but before mouse-button up).

属性源 document
实现版本 Navigator 2.0

描述

The alinkColor property is expressed as a hexadecimal RGB triplet or as one of the string literals listed in Appendix B, "Color Values," in the JavaScript Guide This property is the JavaScript reflection of the ALINK attribute of the BODY tag. You cannot set this property after the HTML source has been through layout.

If you express the color as a hexadecimal RGB triplet, you must use the format rrggbb. For example, the hexadecimal RGB values for salmon are red=FA, green=80, and blue=72, so the RGB triplet for salmon is "FA8072".

示例

The following example sets the color of active links using a string literal:

document.alinkColor="aqua" The following example sets the color of active links to aqua using a hexadecimal triplet:

document.alinkColor="00FFFF"

参看

document.bgColor, document.fgColor, document.linkColor, document.vlinkColor

anchors

An array of objects corresponding to named anchors in source order.

属性源 document
只读
实现版本 Navigator 2.0

描述

You can refer to the Anchor objects in your code by using the anchors array. This array contains an entry for each A tag containing a NAME attribute in a document; these entries are in source order. For example, if a document contains three named anchors whose NAME attributes are anchor1, anchor2, and anchor3, you can refer to the anchors either as:

document.anchors["anchor1"]
document.anchors["anchor2"]
document.anchors["anchor3"] or as:

document.anchors[0]
document.anchors[1]
document.anchors[2] To obtain the number of anchors in a document, use the length property: document.anchors.length. If a document names anchors in a systematic way using natural numbers, you can use the anchors array and its length property to validate an anchor name before using it in operations such as setting location.hash.

applets

An array of objects corresponding to the applets in a document in source order.

属性源 document
只读
实现版本 Navigator 3.0

描述

You can refer to the applets in your code by using the applets array. This array contains an entry for each Applet object (APPLET tag) in a document; these entries are in source order. For example, if a document contains three applets whose NAME attributes are app1, app2, and app3, you can refer to the anchors either as:

document.applets["app1"]
document.applets["app2"]
document.applets["app3"] or as:

document.applets[0]
document.applets[1]
document.applets[2]

bgColor

A string specifying the color of the document background.

属性源 document
实现版本 Navigator 2.0

描述

The bgColor property is expressed as a hexadecimal RGB triplet or as one of the string literals listed in Appendix B, "Color Values," in the JavaScript Guide. This property is the JavaScript reflection of the BGCOLOR attribute of the BODY tag. The default value of this property is set by the user with the preferences dialog box.

示例

The following example sets the color of the document background to aqua using a string literal:

document.bgColor="aqua" The following example sets the color of the document background to aqua using a hexadecimal triplet:

document.bgColor="00FFFF"

参看

document.alinkColor, document.fgColor, document.linkColor, document.vlinkColor

cookie

String value representing all of the cookies associated with this document.

属性源 document
实现版本 Navigator 2.0

domain

Specifies the domain name of the server that served a document.

属性源 document
实现版本 Navigator 3.0

安全性

Navigator 3.0：该属性默认是带有污点的。有关数据污点的更多信息，请看 “JavaScript 的安全性”。

描述

Navigator 3.0: The domain property lets scripts on multiple servers share properties when data tainting is not enabled. With tainting disabled, a script running in one window can read properties of another window only if both windows come from the same Web server. But large Web sites with multiple servers might need to share properties among servers. For example, a script on the host www.royalairways.com might need to share properties with a script on the host search.royalairways.com.

If scripts on two different servers change their domain property so that both scripts have the same domain name, both scripts can share properties. For example, a script loaded from search.royalairways.com could set its domain property to "royalairways.com". A script from www.royalairways.com running in another window could also set its domain property to "royalairways.com". Then, since both scripts have the domain "royalairways.com", these two scripts can share properties, even though they did not originate from the same server.

You can change domain only in a restricted way. Initially, domain contains the hostname of the Web server from which the document was loaded. You can set domain only to a domain suffix of itself. For example, a script from search.royalairways.com can't set its domain property to "search.royalairways". And a script from IWantYourMoney.com cannot set its domain to "royalairways.com".

Once you change the domain property, you cannot change it back to its original value. For example, if you change domain from "search.royalairways.com" to "royalairways.com", you cannot reset it to "search.royalairways.com".

示例

The following statement changes the domain property to "braveNewWorld.com". This statement is valid only if "braveNewWorld.com" is a suffix of the current domain, such as "www.braveNewWorld.com".

document.domain="braveNewWorld.com"

embeds

An array containing an entry for each object embedded in the document.

属性源 document
只读
实现版本 Navigator 3.0

You can refer to embedded objects (created with the EMBED tag) in your code by using the embeds array. This array contains an entry for each EMBED tag in a document in source order. For example, if a document contains three embedded objects whose NAME attributes are e1, e2, and e3, you can refer to the objects either as:

document.embeds["e1"]
document.embeds["e2"]
document.embeds["e3"] or as:

document.embeds[0]
document.embeds[1]
document.embeds[2] Elements in the embeds array may have public callable functions, if they refer to a plug-in that uses LiveConnect. See the JavaScript Guide.

Use the elements in the embeds array to interact with the plug-in that is displaying the embedded object. If a plug-in is not Java-enabled, you cannot do anything with its element in the embeds array. The fields and methods of the elements in the embeds array vary from plug-in to plug-in; see the documentation supplied by the plug-in manufacturer.

When you use the EMBED tag to generate output from a plug-in application, you are not creating a Plugin object.

示例

The following code includes an audio plug-in in a document.

参看

Plugin

fgColor

A string specifying the color of the document (foreground) text.

属性源 document
实现版本 Navigator 2.0

描述

The fgColor property is expressed as a hexadecimal RGB triplet or as one of the string literals listed in Appendix B, "Color Values," in the JavaScript Guide. This property is the JavaScript reflection of the TEXT attribute of the BODY tag. The default value of this property is set by the user with the preferences dialog box You cannot set this property after the HTML source has been through layout.

You can override the value set in the fgColor property in either of the following ways:

Setting the COLOR attribute of the FONT tag.

Using the fontcolor method.

formName

属性源 document
实现版本 Navigator 3.0

The document object contains a separate property for each form in the document. The name of this property is the value of its NAME attribute. See Form for information on Form objects. You cannot add new forms to the document by creating new properties, but you can modify the form by modifying this object.

forms

An array containing an entry for each form in the document.

属性源 document
只读
实现版本 Navigator 3.0

安全性

Navigator 3.0：该属性默认是带有污点的。有关数据污点的更多信息，请看 “JavaScript 的安全性”。

描述

You can refer to the forms in your code by using the forms array (you can also use the form name). This array contains an entry for each Form object (FORM tag) in a document; these entries are in source order. For example, if a document contains three forms whose NAME attributes are form1, form2, and form3, you can refer to the objects in the forms array either as:

document.forms["form1"]
document.forms["form2"]
document.forms["form3"] or as:

document.forms[0]
document.forms[1]
document.forms[2] Additionally, the document object has a separate property for each named form, so you could refer to these forms also as:

document.form1
document.form2
document.form3 For example, you would refer to a Text object named quantity in the second form as document.forms[1].quantity. You would refer to the value property of this Text object as document.forms[1].quantity.value.

The value of each element in the forms array is <object nameAttribute>, where nameAttribute is the NAME attribute of the form.

images

An array containing an entry for each image in the document.

属性源 document
只读
实现版本 Navigator 3.0

You can refer to the images in a document by using the images array. This array contains an entry for each Image object (IMG tag) in a document; the entries are in source order. Images created with the Image constructor are not included in the images array. For example, if a document contains three images whose NAME attributes are im1, im2, and im3, you can refer to the objects in the images array either as:

document.images["im1"]
document.images["im2"]
document.images["im3"] or as:

document.images[0]
document.images[1]
document.images[2]

lastModified

A string representing the date that a document was last modified.

属性源 document
只读
实现版本 Navigator 2.0

安全性

Navigator 3.0：该属性默认是带有污点的。有关数据污点的更多信息，请看 “JavaScript 的安全性”。

描述

The lastModified property is derived from the HTTP header data sent by the web server. Servers generally obtain this date by examining the file's modification date.

The last modified date is not a required portion of the header, and some servers do not supply it. If the server does not return the last modified information, JavaScript receives a 0, which it displays as January 1, 1970 GMT. The following code checks the date returned by lastModified and prints out a value that corresponds to unknown.

lastmod = document.lastModified // get string of last modified date
lastmoddate = Date.parse(lastmod)   // convert modified string to date
if(lastmoddate == 0){               // unknown date (or January 1, 1970 GMT)
   document.writeln("Lastmodified: Unknown")
   } else {
   document.writeln("LastModified: " + lastmod)
}

示例

In the following example, the lastModified property is used in a SCRIPT tag at the end of an HTML file to display the modification date of the page:

document.write("This page updated on " + document.lastModified)

layers

The layers property is an array containing an entry for each layer within the document.

属性源 document
实现版本 Navigator 4.0

描述

You can refer to the layers in your code by using the layers array. This array contains an entry for each Layer object (LAYER or ILAYER tag) in a document; these entries are in source order. For example, if a document contains three layers whose NAME attributes are layer1, layer2, and layer3, you can refer to the objects in the layers array either as:

document.layers["layer1"]
document.layers["layer2"]
document.layers["layer3"] or as:

document.layers[0]
document.layers[1]
document.layers[2] When accessed by integer index, array elements appear in z-order from back to front, where 0 is the bottommost layer and higher layers are indexed by consecutive integers. The index of a layer is not the same as its zIndex property, as the latter does not necessarily enumerate layers with consecutive integers. Adjacent layers can have the same zIndex property values.

These are valid ways of accessing layer objects:

document.layerName
document.layers【索引】
document.layers["layerName"]
// example of using layers property to access nested layers:
document.layers["parentlayer"].layers["childlayer"] Elements of a layers array are JavaScript objects that cannot be set by assignment, though their properties can be set. For example, the statement

document.layers[0]="music" is invalid (and ignored) because it attempts to alter the layers array. However, the properties of the objects in the array readable and some are wri表. For example, the statement

document.layers["suspect1"].left = 100; is valid. This sets the layer's horizontal position to 100. The following example sets the background color to blue for the layer bluehouse which is nested in the layer houses.

document.layers["houses"].layers["bluehouse"].bgColor="blue";

linkColor

A string specifying the color of the document hyperlinks.

属性源 document
实现版本 Navigator 2.0

描述

The linkColor property is expressed as a hexadecimal RGB triplet or as one of the string literals listed in the JavaScript Guide. This property is the JavaScript reflection of the LINK attribute of the BODY tag. The default value of this property is set by the user with the preferences dialog box. You cannot set this property after the HTML source has been through layout.

示例

The following example sets the color of document links to aqua using a string literal:

document.linkColor="aqua" The following example sets the color of document links to aqua using a hexadecimal triplet:

document.linkColor="00FFFF"

参看

document.alinkColor, document.bgColor, document.fgColor, document.vlinkColor

links

An array of objects corresponding to Area and Link objects in source order.

属性源 document
只读
实现版本 Navigator 2.0

安全性

Navigator 3.0：该属性默认是带有污点的。有关数据污点的更多信息，请看 “JavaScript 的安全性”。

描述

You can refer to the Area and Link objects in your code by using the links array. This array contains an entry for each Area (<AREA HREF="..."> tag) and Link (<A HREF="..."> tag) object in a document in source order. It also contains links created with the link method. For example, if a document contains three links, you can refer to them as:

document.links[0]
document.links[1]
document.links[2]

plugins

An array of objects corresponding to Plugin objects in source order.

属性源 document
只读
实现版本 Navigator 3.0

You can refer to the Plugin objects in your code by using the plugins array. This array contains an entry for each Plugin object in a document in source order. For example, if a document contains three plugins, you can refer to them as:

document.plugins[0]
document.plugins[1]
document.plugins[2]

The vlinkColor property is expressed as a hexadecimal RGB triplet or as one of the string literals listed in the JavaScript Guide. This property is the JavaScript reflection of the VLINK attribute of the BODY tag. The default value of this property is set by the user with the preferences dialog box. You cannot set this property after the HTML source has been through layout.