The nsIWebProgressListener interface is implemented by clients wishing to
listen in on the progress associated with the loading of asynchronous
requests in the context of a nsIWebProgress instance as well as any child
nsIWebProgress instances. nsIWebProgress.idl describes the parent-child
relationship of nsIWebProgress instances.
Notification indicating the state has changed for one of the requests
associated with aWebProgress.
| aWebProgress | The nsIWebProgress instance that fired the notification |
| aRequest | The nsIRequest that has changed state. |
| aStateFlags | Flags indicating the new state. This value is a combination of one of the State Transition Flags and one or more of the State Type Flags defined above. Any undefined bits are reserved for future use. |
| aStatus | Error status code associated with the state change. This parameter should be ignored unless aStateFlags includes the STATE_STOP bit. The status code indicates success or failure of the request associated with the state change. NOTE: aStatus may be a success code even for server generated errors, such as the HTTP 404 error. In such cases, the request itself should be queried for extended error information (e.g., for HTTP requests see nsIHttpChannel). |
Notification that the progress has changed for one of the requests
associated with aWebProgress. Progress totals are reset to zero when all
requests in aWebProgress complete (corresponding to onStateChange being
called with aStateFlags including the STATE_STOP and STATE_IS_WINDOW
flags).
NOTE: If any progress value is unknown, or if its value would exceed the
maximum value of type long, then its value is replaced with -1.
NOTE: If the object also implements nsIWebProgressListener2 and the caller
knows about that interface, this function will not be called. Instead,
nsIWebProgressListener2::onProgressChange64 will be called.
| aWebProgress | The nsIWebProgress instance that fired the notification. |
| aRequest | The nsIRequest that has new progress. |
| aCurSelfProgress | The current progress for aRequest. |
| aMaxSelfProgress | The maximum progress for aRequest. |
| aCurTotalProgress | The current progress for all requests associated with aWebProgress. |
| aMaxTotalProgress | The total progress for all requests associated with aWebProgress. |
Called when the location of the window being watched changes. This is not
when a load is requested, but rather once it is verified that the load is
going to occur in the given window. For instance, a load that starts in a
window might send progress and status messages for the new site, but it
will not send the onLocationChange until we are sure that we are loading
this new page here.
| aWebProgress | The nsIWebProgress instance that fired the notification. |
| aRequest | The associated nsIRequest. This may be null in some cases. |
| aLocation | The URI of the location that is being loaded. |
| aFlags | This is a value which explains the situation or the reason why the location has changed. |
Notification that the status of a request has changed. The status message
is intended to be displayed to the user (e.g., in the status bar of the
browser).
| aWebProgress | The nsIWebProgress instance that fired the notification. |
| aRequest | The nsIRequest that has new status. |
| aStatus | This value is not an error code. Instead, it is a numeric value that indicates the current status of the request. This interface does not define the set of possible status codes. NOTE: Some status values are defined by nsITransport and nsISocketTransport. |
| aMessage | Localized text corresponding to aStatus. |
Notification called for security progress. This method will be called on
security transitions (eg HTTP -> HTTPS, HTTPS -> HTTP, FOO -> HTTPS) and
after document load completion. It might also be called if an error
occurs during network loading.
NOTE: These notifications will only occur if a security package is
installed.
| aWebProgress | The nsIWebProgress instance that fired the notification. |
| aRequest | The nsIRequest that has new security state. |
| aState | A value composed of the Security State Flags and the Security Strength Flags listed above. Any undefined bits are reserved for future use. |
State Transition Flags
These flags indicate the various states that requests may transition
through as they are being loaded. These flags are mutually exclusive.
For any given request, onStateChange is called once with the STATE_START
flag, zero or more times with the STATE_TRANSFERRING flag or once with the
STATE_REDIRECTING flag, and then finally once with the STATE_STOP flag.
NOTE: For document requests, a second STATE_STOP is generated (see the
description of STATE_IS_WINDOW for more details).
STATE_START
This flag indicates the start of a request. This flag is set when a
request is initiated. The request is complete when onStateChange is
called for the same request with the STATE_STOP flag set.
STATE_REDIRECTING
This flag indicates that a request is being redirected. The request
passed to onStateChange is the request that is being redirected. When a
redirect occurs, a new request is generated automatically to process the
new request. Expect a corresponding STATE_START event for the new
request, and a STATE_STOP for the redirected request.
STATE_TRANSFERRING
This flag indicates that data for a request is being transferred to an
end consumer. This flag indicates that the request has been targeted,
and that the user may start seeing content corresponding to the request.
STATE_NEGOTIATING
This flag is not used.
STATE_STOP
This flag indicates the completion of a request. The aStatus parameter
to onStateChange indicates the final status of the request.
State Type Flags
These flags further describe the entity for which the state transition is
occuring. These flags are NOT mutually exclusive (i.e., an onStateChange
event may indicate some combination of these flags).
STATE_IS_REQUEST
This flag indicates that the state transition is for a request, which
includes but is not limited to document requests. (See below for a
description of document requests.) Other types of requests, such as
requests for inline content (e.g., images and stylesheets) are
considered normal requests.
STATE_IS_DOCUMENT
This flag indicates that the state transition is for a document request.
This flag is set in addition to STATE_IS_REQUEST. A document request
supports the nsIChannel interface and its loadFlags attribute includes
the nsIChannel::LOAD_DOCUMENT_URI flag.
A document request does not complete until all requests associated with
the loading of its corresponding document have completed. This includes
other document requests (e.g., corresponding to HTML <iframe> elements).
The document corresponding to a document request is available via the
DOMWindow attribute of onStateChange’s aWebProgress parameter.
STATE_IS_NETWORK
This flag indicates that the state transition corresponds to the start
or stop of activity in the indicated nsIWebProgress instance. This flag
is accompanied by either STATE_START or STATE_STOP, and it may be
combined with other State Type Flags.
Unlike STATE_IS_WINDOW, this flag is only set when activity within the
nsIWebProgress instance being observed starts or stops. If activity
only occurs in a child nsIWebProgress instance, then this flag will be
set to indicate the start and stop of that activity.
For example, in the case of navigation within a single frame of a HTML
frameset, a nsIWebProgressListener instance attached to the
nsIWebProgress of the frameset window will receive onStateChange calls
with the STATE_IS_NETWORK flag set to indicate the start and stop of
said navigation. In other words, an observer of an outer window can
determine when activity, that may be constrained to a child window or
set of child windows, starts and stops.
STATE_IS_WINDOW
This flag indicates that the state transition corresponds to the start
or stop of activity in the indicated nsIWebProgress instance. This flag
is accompanied by either STATE_START or STATE_STOP, and it may be
combined with other State Type Flags.
This flag is similar to STATE_IS_DOCUMENT. However, when a document
request completes, two onStateChange calls with STATE_STOP are
generated. The document request is passed as aRequest to both calls.
The first has STATE_IS_REQUEST and STATE_IS_DOCUMENT set, and the second
has the STATE_IS_WINDOW flag set (and possibly the STATE_IS_NETWORK flag
set as well – see above for a description of when the STATE_IS_NETWORK
flag may be set). This second STATE_STOP event may be useful as a way
to partition the work that occurs when a document request completes.
State Modifier Flags
These flags further describe the transition which is occuring. These
flags are NOT mutually exclusive (i.e., an onStateChange event may
indicate some combination of these flags).
STATE_RESTORING
This flag indicates that the state transition corresponds to the start
or stop of activity for restoring a previously-rendered presentation.
As such, there is no actual network activity associated with this
request, and any modifications made to the document or presentation
when it was originally loaded will still be present.
State Security Flags
These flags describe the security state reported by a call to the
onSecurityChange method. These flags are mutually exclusive.
STATE_IS_INSECURE
This flag indicates that the data corresponding to the request
was received over an insecure channel.
STATE_IS_BROKEN
This flag indicates an unknown security state. This may mean that the
request is being loaded as part of a page in which some content was
received over an insecure channel.
STATE_IS_SECURE
This flag indicates that the data corresponding to the request was
received over a secure channel. The degree of security is expressed by
STATE_SECURE_HIGH, STATE_SECURE_MED, or STATE_SECURE_LOW.
Mixed active content flags
May be set in addition to the State Security Flags, to indicate that
mixed active content has been encountered.
STATE_BLOCKED_MIXED_ACTIVE_CONTENT
Mixed active content has been blocked from loading.
STATE_LOADED_MIXED_ACTIVE_CONTENT
Mixed active content has been loaded. State should be STATE_IS_BROKEN.
Mixed display content flags
May be set in addition to the State Security Flags, to indicate that
mixed display content has been encountered.
STATE_BLOCKED_MIXED_DISPLAY_CONTENT
Mixed display content has been blocked from loading.
STATE_LOADED_MIXED_DISPLAY_CONTENT
Mixed display content has been loaded. State should be STATE_IS_BROKEN.
Tracking content flags
May be set in addition to the State security Flags, to indicate that
tracking content has been encountered.
STATE_BLOCKED_TRACKING_CONTENT
Tracking content has been blocked from loading.
STATE_LOADED_TRACKING_CONTENT
Tracking content has been loaded.
Security Strength Flags
These flags describe the security strength and accompany STATE_IS_SECURE
in a call to the onSecurityChange method. These flags are mutually
exclusive.
These flags are not meant to provide a precise description of data
transfer security. These are instead intended as a rough indicator that
may be used to, for example, color code a security indicator or otherwise
provide basic data transfer security feedback to the user.
STATE_SECURE_HIGH
This flag indicates a high degree of security.
STATE_SECURE_MED
This flag indicates a medium degree of security.
STATE_SECURE_LOW
This flag indicates a low degree of security.
State bits for EV == Extended Validation == High Assurance
These flags describe the level of identity verification
in a call to the onSecurityChange method.
STATE_IDENTITY_EV_TOPLEVEL
The topmost document uses an EV cert.
NOTE: Available since Gecko 1.9
Flags for onLocationChange
LOCATION_CHANGE_SAME_DOCUMENT
This flag is on when |aWebProgress| did not load a new document.
For example, the location change is due to an anchor scroll or a
pushState/popState/replaceState.
LOCATION_CHANGE_ERROR_PAGE
This flag is on when |aWebProgress| redirected from the requested
contents to an internal page to show error status, such as