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History

Contains an array of information on the URLs that the client has visited within a window. This information is stored in a history list and is accessible through the browser's Go menu.

Client-side object

Implemented in

JavaScript 1.0

JavaScript 1.1: added current, next, and previous properties.

Created by

History objects are predefined JavaScript objects that you access through the history property of a window object.

Description

To change a window's current URL without generating a history entry, you can use the Location.replace method. This replaces the current page with a new one without generating a history entry. See Location.replace.

You can refer to the history entries by using the window.history array. This array contains an entry for each history entry in source order. Each array entry is a string containing a URL. For example, if the history list contains three named entries, these entries are reflected as history[0], history[1], and history[2].

If you access the history array without specifying an array element, the browser returns a string of HTML which displays a table of URLs, each of which is a link.

Property Summary

Property Description
current

Specifies the URL of the current history entry.

length

Reflects the number of entries in the history list.

next

Specifies the URL of the next history entry.

previous

Specifies the URL of the previous history entry.

Method Summary

Method Description
back

Loads the previous URL in the history list.

forward

Loads the next URL in the history list.

go

Loads a URL from the history list.

In addition, this object inherits the watch and unwatch methods from Object.

Examples

Example 1. The following example goes to the URL the user visited three clicks ago in the current window.

history.go(-3)
Example 2. You can use the history object with a specific window or frame. The following example causes window2 to go back one item in its window (or session) history:

window2.history.back()
Example 3. The following example causes the second frame in a frameset to go back one item:

parent.frames[1].history.back()
Example 4. The following example causes the frame named frame1 in a frameset to go back one item:

parent.frame1.history.back()
Example 5. The following example causes the frame named frame2 in window2 to go back one item:

window2.frame2.history.back()
Example 6. The following code determines whether the first entry in the history array contains the string "NETSCAPE". If it does, the function myFunction is called.

if (history[0].indexOf("NETSCAPE") != -1) {
   myFunction(history[0])
}
Example 7. The following example displays the entire history list:

document.writeln("<B>history is</B> " + history)
This code displays output similar to the following:

history is
Welcome to Netscape http://home.netscape.com/
Sun Microsystems http://www.sun.com/
Royal Airways http://www.supernet.net/~dugbrown/

See also

Location, Location.replace


back

Loads the previous URL in the history list.

Method of

History

Implemented in

JavaScript 1.0

Syntax

back()

Parameters

None

Description

This method performs the same action as a user choosing the Back button in the browser. The back method is the same as history.go(-1).

Examples

The following custom buttons perform the same operation as the browser's Back button:

<P><INPUT TYPE="button" VALUE="< Go Back"
   onClick="history.back()">
<P><INPUT TYPE="button" VALUE="> Go Back"
   onClick="myWindow.back()">

See also

History.forward, History.go


current

A string specifying the complete URL of the current history entry.

Property of

History

Read-only

Implemented in

JavaScript 1.1

Security

JavaScript 1.1: This property is tainted by default. It has no value of data tainting is disabled. For information on data tainting, see the Client-Side JavaScript Guide.

JavaScript 1.2: Getting the value of this property requires the UniversalBrowserRead privilege. It has no value if you do not have this privilege. For information on security, see the Client-Side JavaScript Guide.

Examples

The following example determines whether history.current contains the string "netscape.com". If it does, the function myFunction is called.

if (history.current.indexOf("netscape.com") != -1) {
   myFunction(history.current)
}

See also

History.next, History.previous


forward

Loads the next URL in the history list.

Method of

History

Implemented in

JavaScript 1.0

Syntax

forward()

Parameters

None

Description

This method performs the same action as a user choosing the Forward button in the browser. The forward method is the same as history.go(1).

Examples

The following custom buttons perform the same operation as the browser's Forward button:

<P><INPUT TYPE="button" VALUE="< Forward"
   onClick="history.forward()">
<P><INPUT TYPE="button" VALUE="> Forward"
   onClick="myWindow.forward()">

See also

History.back, History.go


go

Loads a URL from the history list.

Method of

History

Implemented in

JavaScript 1.0

Syntax

go(delta)
go(location)

Parameters

delta

An integer representing a relative position in the history list.

location

A string representing all or part of a URL in the history list.

Description

The go method navigates to the location in the history list determined by the specified parameter.

If the delta argument is 0, the browser reloads the current page. If it is an integer greater than 0, the go method loads the URL that is that number of entries forward in the history list; otherwise, it loads the URL that is that number of entries backward in the history list.

The location argument is a string. Use location to load the nearest history entry whose URL contains location as a substring. Matching the URL to the location parameter is case-insensitive. Each section of a URL contains different information. See Location for a description of the URL components.

The go method creates a new entry in the history list. To load a URL without creating an entry in the history list, use Location.replace.

Examples

The following button navigates to the nearest history entry that contains the string "home.netscape.com":

<P><INPUT TYPE="button" VALUE="Go"
   onClick="history.go('home.netscape.com')">
The following button navigates to the URL that is three entries backward in the history list:

<P><INPUT TYPE="button" VALUE="Go"
   onClick="history.go(-3)">

See also

History.back, History.forward, Location.reload, Location.replace


length

The number of elements in the history array.

Property of

History

Read-only

Implemented in

JavaScript 1.0

Security

JavaScript 1.2: Getting the value of this property requires the UniversalBrowserRead privilege. For information on security, see the Client-Side JavaScript Guide.


next

A string specifying the complete URL of the next history entry.

Property of

History

Read-only

Implemented in

JavaScript 1.1

Security

JavaScript 1.1: This property is tainted by default. It has no value if data tainting is disabled. For information on data tainting, see the Client-Side JavaScript Guide.

JavaScript 1.2: Getting the value of this property requires the UniversalBrowserRead privilege. It has no value if you do not have this privilege. For information on security, see the Client-Side JavaScript Guide.

Description

The next property reflects the URL that would be used if the user chose Forward from the Go menu.

Examples

The following example determines whether history.next contains the string "NETSCAPE.COM". If it does, the function myFunction is called.

if (history.next.indexOf("NETSCAPE.COM") != -1) {
   myFunction(history.next)
}

See also

History.current, History.previous


previous

A string specifying the complete URL of the previous history entry.

Property of

History

Read-only

Implemented in

JavaScript 1.1

Security

JavaScript 1.1: This property is tainted by default. It has no value of data tainting is disabled. For information on data tainting, see the Client-Side JavaScript Guide.

JavaScript 1.2: Getting the value of this property requires the UniversalBrowserRead privilege. It has no value if you do not have this privilege. For information on security, see the Client-Side JavaScript Guide.

Description

The previous property reflects the URL that would be used if the user chose Back from the Go menu.

Examples

The following example determines whether history.previous contains the string "NETSCAPE.COM". If it does, the function myFunction is called.

if (history.previous.indexOf("NETSCAPE.COM") != -1) {
   myFunction(history.previous)
}

See also

History.current, History.next


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Last Updated: 11/16/98 12:56:29

Copyright (c) 1998 Netscape Communications Corporation