如何知道是否通过用户单击新选项卡按钮打开一个新选项卡

Question

在firefox webextensions中，如何以哪种方式知道新的选项卡？

• 用户单击"新标签"按钮（ ）？
• 通过用户单击诸如<a href="http://www.google.com/">之类的链接？

  注意：我不在乎window.open()

  是否打开一个新标签

我发现，在chrome.tabs.Tab.onCreated的回调中，有一个参数，假设它命名为 firefoxTab：

• 对于通过单击 打开的选项卡，其URL是about:newtab
• 对于通过单击<a href="" target="_blank">打开的选项卡，其URL是about:blank

但，如果启动Firefox后的第二个选项卡，则通过单击" "打开，它的URL将是about:blank，而不是about:newtab。我认为这是一个Firefox缺陷，已在Bugzilla上发布了一个错误。

与此同时，还有其他方法可以做吗？

Answer 1

我可以确认这发生在Firefox 52.0中（夜间测试，Firefox 55.0A1产生了相似的结果）。

重新启动时首次单击+发生的事件是：

tabs.onUpdated                   ->  arg[0]= 1 :: arg[1]= Object { status: "loading" } :: arg[2]= Object { id: 1, index: 1, windowId: 1, selected: false, highlighted: false, active: false, pinned: false, status: "complete", incognito: false, width: 1098, height: 812, audible: false, mutedInfo: { muted: false}, cookieStoreId: "firefox-default", url: "about:blank", title: "New Tab"}
tabs.onActivated                 ->  arg[0]= Object { tabId: 1, windowId: 1 }          
tabs.onHighlighted               ->  arg[0]= Object { tabIds: Array[1], windowId: 1 }          
tabs.onCreated                   ->  arg[0]= Object { id: 1, index: 1, windowId: 1, selected: true, highlighted: true, active: true, pinned: false, status: "complete", incognito: false, width: 1098, height: 812, audible: false, mutedInfo: { muted: false}, cookieStoreId: "firefox-default", url: "about:blank", title: "New Tab"}
tabs.onUpdated                   ->  arg[0]= 1 :: arg[1]= Object { status: "loading", url: "about:newtab" } :: arg[2]= Object { id: 1, index: 1, windowId: 1, selected: true, highlighted: true, active: true, pinned: false, status: "complete", incognito: false, width: 1098, height: 812, audible: false, mutedInfo: { muted: false}, cookieStoreId: "firefox-default", url: "about:newtab", title: "New Tab"}
webNavigation.onBeforeNavigate   ->  arg[0]= Object { url: "about:newtab", timeStamp: 1489473167445, frameId: 0, parentFrameId: -1, tabId: 1 }          
webNavigation.onCommitted        ->  arg[0]= Object { url: "about:newtab", timeStamp: 1489473167466, frameId: 0, parentFrameId: -1, tabId: 1, transitionType: "link", transitionQualifiers: Array[0] }          
webNavigation.onDOMContentLoaded ->  arg[0]= Object { url: "about:newtab", timeStamp: 1489473167718, frameId: 0, parentFrameId: -1, tabId: 1 }          
tabs.onUpdated                   ->  arg[0]= 1 :: arg[1]= Object { status: "complete" } :: arg[2]= Object { id: 1, index: 1, windowId: 1, selected: true, highlighted: true, active: true, pinned: false, status: "complete", incognito: false, width: 1098, height: 812, audible: false, mutedInfo: { muted: false}, cookieStoreId: "firefox-default", url: "about:newtab", title: "New Tab"}
webNavigation.onCompleted        ->  arg[0]= Object { url: "about:newtab", timeStamp: 1489473167914, frameId: 0, parentFrameId: -1, tabId: 1 }          
tabs.onUpdated                   ->  arg[0]= 1 :: arg[1]= Object { status: undefined } :: arg[2]= Object { id: 1, index: 1, windowId: 1, selected: true, highlighted: true, active: true, pinned: false, status: "complete", incognito: false, width: 1098, height: 812, audible: false, mutedInfo: { muted: false}, cookieStoreId: "firefox-default", url: "about:newtab", title: "New Tab"}

在+上单击第二次时的事件是（是的，事件大大少，没有webNavigation事件）：

tabs.onActivated   ->  arg[0]= Object { tabId: 2, windowId: 1 }          
tabs.onHighlighted ->  arg[0]= Object { tabIds: Array[1], windowId: 1 }          
tabs.onCreated     ->  arg[0]= Object { id: 2, index: 2, windowId: 1, selected: true, highlighted: true, active: true, pinned: false, status: "complete", incognito: false, width: 1098, height: 812, audible: false, mutedInfo: {"muted: false}, cookieStoreId: "firefox-default", url: "about:newtab", title: "New Tab"}

随后的+点击导致类似的事件。有时会发射其他事件。此外，还有更多事件起火，具体取决于about:newtab页的内容。

相反，当单击<a href="" target="_blank">时发生了许多其他事件。仅tabs.onCreated事件是：

tabs.onCreated ->  arg[0]= Object { id: 3, index: 2, windowId: 1, selected: true, highlighted: true, active: true, pinned: false, status: "loading", incognito: false, width: 1098, height: 812, audible: false, mutedInfo: {"muted: false}, cookieStoreId: "firefox-default", url: "about:blank", title: "Connecting…"}

如果要区分，看来可以查看tabs.onCreated事件中提供的title和url。对于链接，您有：

url: "about:blank", title: "Connecting…"

单击+，您有以下两个：

url: "about:blank", title: "New Tab"   //First `+`
url: "about:newtab", title: "New Tab"  //Subsequent `+`