How to detect a long touch pressure with javascript for android and iphone?

Question

How to detect a long touch pressure with javascript for android and iphone? native javascript or jquery...

I want something that sound like :

Answer 1

For cross platform developers:

Mouseup/down seemed to work okay on android - but not all devices ie (samsung tab4). Did not work at all on iOS.

Further research its seems that this is due to the element having selection and the native magnification interupts the listener.

This event listener enables a thumbnail image to be opened in a bootstrap modal, if the user holds the image for 500ms.

It uses a responsive image class therefore showing a larger version of the image. This piece of code has been fully tested upon (iPad/Tab4/TabA/Galaxy4):

var pressTimer;  
$(".thumbnail").on('touchend', function (e) {
   clearTimeout(pressTimer);
}).on('touchstart', function (e) {
   var target = $(e.currentTarget);
   var imagePath = target.find('img').attr('src');
   var title = target.find('.myCaption:visible').first().text();
   $('#dds-modal-title').text(title);
   $('#dds-modal-img').attr('src', imagePath);
   // Set timeout
   pressTimer = window.setTimeout(function () {
      $('#dds-modal').modal('show');
   }, 500)
});

Answer 2

This better solution based on @Joshua, sometimes the code need to be called directly inside event (some web API require user acction to trigger something) for this case you can use this modification:

var longtouch;
var timer;
//length of time we want the user to touch before we do something
var touchduration = 500;

function touchstart() {
    longtouch = false;

    timer = setTimeout(function() {
       longtouch = true;
       timer = null
    }, touchduration);
}

function touchend() {
    if (timer) {
        clearTimeout(timer);
        timer = null;
    }
    if (longtouch) {
        // your long acction inside event
        longtouch = false;
    }
}

in setTimeout you set the flag to true and inside touchend, you check if it was set.