内容表

• 句法
• addListener syntax
• Additional objects
• 浏览器兼容性
• 范例

downloads.onChanged

onChanged() event of the downloads API is fired when any of a downloads.DownloadItem 's properties changes (except for bytesReceived ).

The listener is passed a downloadDelta as a parameter — an object containing the downloadId 的 downloads.DownloadItem object in question, plus the status of all the properties that changed.

句法

browser.downloads.onChanged.addListener(listener)
浏览器

.

downloads

.

onChanged

.


removeListener


(

listener

)

浏览器

.

downloads

.

onChanged

.


hasListener


(

listener

)


					

Events have three functions:

addListener(callback)

Adds a listener to this event.

removeListener(listener)

Stop listening to this event. The listener argument is the listener to remove.

hasListener(listener)

Check whether a given listener is registered for this event. Returns true if it is listening, false 否则。

addListener syntax

参数

callback

A callback function that will be called when this event occurs. This function will be passed the following arguments:

downloadDelta

An 对象 表示 downloads.DownloadItem object that changed, and the status of all the properties that changed in it.

Additional objects

downloadDelta

downloadDelta object has the following properties available:

id

An integer 表示 id 的 downloads.DownloadItem that changed.

url 可选

A downloads.StringDelta object describing a change in a downloads.DownloadItem 's url .

filename 可选

A downloads.StringDelta object describing a change in a downloads.DownloadItem 's filename .

danger 可选

A downloads.StringDelta object describing a change in a downloads.DownloadItem 's danger .

mime 可选

A downloads.StringDelta object describing a change in a downloads.DownloadItem 's mime .

startTime 可选

A downloads.StringDelta object describing a change in a downloads.DownloadItem 's startTime .

endTime 可选

A downloads.StringDelta object describing a change in a downloads.DownloadItem 's endTime .

state 可选

A downloads.StringDelta object describing a change in a downloads.DownloadItem 's state .

canResume 可选

A downloads.BooleanDelta object describing a change in a downloads.DownloadItem 's canResume 状态。

paused 可选

A downloads.BooleanDelta object describing a change in a downloads.DownloadItem 's paused 状态。

error 可选

A downloads.StringDelta object describing a change in a downloads.DownloadItem 's error 状态。

totalBytes 可选

A downloads.DoubleDelta object describing a change in a downloads.DownloadItem 's totalBytes .

fileSize 可选

A downloads.DoubleDelta object describing a change in a downloads.DownloadItem 's fileSize .

exists 可选

A downloads.BooleanDelta object describing a change in a downloads.DownloadItem 's exists 状态。

浏览器兼容性

BCD tables only load in the browser

范例

Log a message when downloads complete:

function handleChanged(delta) {
  if (delta.state && delta.state.current === "complete") {
    console.log(`Download ${delta.id} has completed.`);
  }
}
browser.downloads.onChanged.addListener(handleChanged);

						

注意： This API is based on Chromium's chrome.downloads API。

Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.

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最后修改： Oct 26, 2021 , 由 MDN 贡献者

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