Why is Input.dispatchMouseEvent not dispatching an event?

Question

I'm trying to dispatch an IsTrusted event that simulates the user clicking a certain place on the screen. I'm trying this out through a Chrome Extension, although I'm not having much luck. There are no errors in the console, and my giant screen-wide button isn't being clicked. Here is my background.js:

chrome.browserAction.onClicked.addListener(function(tab) {
    chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
        var activeTab = tabs[0];
        chrome.runtime.onMessage.addListener(
            function(request, sender, sendResponse) {
              if( request.message === "clickElement" ) {
                chrome.debugger.attach({tabId:tab.id}, "1.2", function(debugg) {
                    chrome.debugger.sendCommand(
                        {tabId:tab.id}, "Debugger.enable", {},
                        function() {
                            chrome.debugger.sendCommand({tabId:tab.id}, "Input.dispatchMouseEvent", 
                            {
                                type:"mousePressed",
                                x:parseFloat(request.x),
                                y:parseFloat(request.y)
                            })
                        })
                })
              }
            }
        );
        chrome.tabs.sendMessage(activeTab.id, {"message": "runbot"});
    });
});

And my content.js just sends the clickElement message with the coordinates of the button.

Any ideas?

Are you sure you can dispatch trusted events? Isn't that the whole point: to be sure whether an event comes from a user interaction or not? — sjahan, Dec 19 '19 at 13:34
@sjahan I saw this answer: https://stackoverflow.com/a/53488689/9969164 and it seems like you can do it using the debugger interface. — MoonBarc, Dec 19 '19 at 13:37
For a click, you need the sequence `MousePressed` followed by `MouseReleased`. You could also try [this approach](https://stackoverflow.com/a/43331339/3930351) — Iván Nokonoko, Dec 19 '19 at 13:48
No, but many times `IsTrusted` is not needed to perform a click on an element. — Iván Nokonoko, Dec 19 '19 at 14:09

avalanche1 · Accepted Answer · 2021-12-31T17:42:39.520

What you need to do is remove this nonsense:

chrome.debugger.sendCommand(
                        {tabId:tab.id}, "Debugger.enable", {},

And add button: "left" prop to the parameters object:

chrome.browserAction.onClicked.addListener(function(tab) {
    chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
        var activeTab = tabs[0];
        chrome.runtime.onMessage.addListener(
            function(request, sender, sendResponse) {
              if( request.message === "clickElement" ) {
                chrome.debugger.attach({tabId:tab.id}, "1.2", function(debugg) {

                            chrome.debugger.sendCommand({tabId:tab.id}, "Input.dispatchMouseEvent", 
                            {
                                type:"mousePressed",
                                button: "left",
                                x:parseFloat(request.x),
                                y:parseFloat(request.y)
                            })

                })
              }
            }
        );
        chrome.tabs.sendMessage(activeTab.id, {"message": "runbot"});
    });
});

Also make sure you have the "debugger" permission in you manifest.json.

ps. When debugger attaches you should see this bar appear just below the address bar saying smth like '${extn. name} is executing browser debug':

Why is Input.dispatchMouseEvent not dispatching an event?

1 Answers1