macOS How do I recognize a mouseclick in a webpage from a Safari extension?

[Switz213]

'm a bit of a noob, but I tried all of the obvious things. Perhaps my javascript is just terrible and that's why, but onmousedown = func; doesn't work. etc.

    function performCommand(event)
{
    /*removed*/
//It reaches this point
        document.body.onclick = function() { 
        //Never reaches this point
/*removed*/
    }
}

http://stackoverflow.com/questions/...useclick-in-a-webpage-from-a-safari-extension