Mousedown and mouseup on ios acts different than on safari and firefox on mac

Question

I'm adding two eventListener()'s to a html button so I can detect a long press. It works on safari and firefox on mac but when I open the same webpage in ios on an iphone/ipad or in a simulator the copy/paste popup menu appears.

I found Preventing default context menu on longpress / longclick in mobile Safari (iPad / iPhone) and How to disable the default behavior of an Anchor in jQuery Mobile (iOS).

The popup was solved adding the following to css:

html {
    -webkit-user-select: none !important;
    -webkit-touch-callout: none !important;
}

If the button is held x ms. it shall perform some function. When I print mouse_delta in an alert message it shows 2 (ms.) even though I hold down the button a few seconds. So it might be a powersaving feature in ios.

Javascript (partial):

var hometeam_goal = document.getElementById("add_goal_hometeam");

hometeam_goal.addEventListener("mousedown", function homegoal_md (event) {
    mouse_start = Date.now();
}

hometeam_goal.addEventListener("mouseup", function homegoal_mu (event) {
    mouse_delta = Date.now() - mouse_start;
    if (mouse_delta < foo) {
        <do something>
    }
}

How can I work around this on ios?

regards Claus