How to prevent doubletap zoom in iOS and Android

Question

I am building a web app using Jquery Mobile for use on a desktop, iPad and Android phone. I want the user to be able to tap a button to increment (or decrement) a value. My code works fine on a desktop, but on the iPad and Android, when the user taps rapidly, the screen zooms instead of the value incrementing. I have been trying to implement the solution here: Safari iPad : prevent zoom on double-tap (and in particular the refinement provided by Christopher Thomas.

Here is my code for the button and value:

    <div class="content">
        <div id ="status_page" data-role="page">
            <div data-role="content" data-theme="d">
                <div id="val">1</div>
                <div id="but" data-role="button">Click</div>
            </div>
        </div>
    </div>

Here is my event handler for a click on the button (btw - I think the parameters in Christopher's answer were the wrong way round):

        $(".content") .on("click",$("#but"),function(){
            var but_val = parseInt($("#val").text());
            $("#val").text(but_val+1);
        });

...and here is the nodoubletap function:

(function($) {
$.fn.nodoubletapzoom = function() {
    if($("html.touch").length == 0) return;

    $(this).bind('touchstart', function preventZoom(e){
        var t2 = e.timeStamp;
        var t1 = $(this).data('lastTouch') || t2;
        var dt = t2 - t1;
        var fingers = e.originalEvent.touches.length;
        $(this).data('lastTouch', t2);
        if (!dt || dt > 500 || fingers > 1){
            return; // not double-tap
        }
        e.preventDefault(); // double tap - prevent the zoom
        // also synthesize click events we just swallowed up
        $(this).trigger('click');
    });
};
})(jQuery);

This function is trapping the double tap correctly. However, the trigger function at the end is not working (the event is not being fired). If I substitute $(this).trigger('click'); with $('#but').trigger('click'); then everything works as it should. I want this to work for a number of different buttons, so I need to be able to trigger the event based on the object that called the touchstart event. Can anyone help me to fix this please.

Answer 1

ok, so "engeeaitch" the final solution was in the following jsfiddle?

http://jsfiddle.net/GZEM7/18/

and the solution was to replace

$(this).trigger("click"):

with

$(e.target).trigger("click");

and of course, I removed your IOS testing because then it'll work on chrome and android devices :D

thats the final solution? Cool! I'm going to update my code with the new version, I think it'll be better

the final code is:

$.fn.nodoubletapzoom = function() {
    $(this).bind('touchstart', function preventZoom(e){
        var t2 = e.timeStamp;
        var t1 = $(this).data('lastTouch') || t2;
        var dt = t2 - t1;
        var fingers = e.originalEvent.touches.length;
        $(this).data('lastTouch', t2);
        if (!dt || dt > 500 || fingers > 1){
            return; // not double-tap
        }
        e.preventDefault(); // double tap - prevent the zoom
        // also synthesize click events we just swallowed up
        $(e.target).trigger('click');
    });
};
})(jQuery);

$(document).on('pageinit',"#status_page", function(){
        $("body").nodoubletapzoom();
        $(".content").on("click", "#but", function() {
            var curr_val = parseInt($("#val").text());
            $("#val").text(curr_val + 1);
        });
});