Twitter Bootstrap modal on mobile devices

Question

Bootstrap modals don\'t work correctly on Android and iOS. The issue tracker acknowledges the problem but does not offer a working solution:

Modals in 2.0 are broke

Answer 1

My solution...

Ver en jsfiddle

//Fix modal mobile Boostrap 3
function Show(id){
    //Fix CSS
    $(".modal-footer").css({"padding":"19px 20px 20px","margin-top":"15px","text-align":"right","border-top":"1px solid #e5e5e5"});
    $(".modal-body").css("overflow-y","auto");
    //Fix .modal-body height
    $('#'+id).on('shown.bs.modal',function(){
        $("#"+id+">.modal-dialog>.modal-content>.modal-body").css("height","auto");
        h1=$("#"+id+">.modal-dialog").height();
        h2=$(window).height();
        h3=$("#"+id+">.modal-dialog>.modal-content>.modal-body").height();
        h4=h2-(h1-h3);      
        if($(window).width()>=768){
            if(h1>h2){
                $("#"+id+">.modal-dialog>.modal-content>.modal-body").height(h4);
            }
            $("#"+id+">.modal-dialog").css("margin","30px auto");
            $("#"+id+">.modal-dialog>.modal-content").css("border","1px solid rgba(0,0,0,0.2)");
            $("#"+id+">.modal-dialog>.modal-content").css("border-radius",6);               
            if($("#"+id+">.modal-dialog").height()+30>h2){
                $("#"+id+">.modal-dialog").css("margin-top","0px");
                $("#"+id+">.modal-dialog").css("margin-bottom","0px");
            }
        }
        else{
            //Fix full-screen in mobiles
            $("#"+id+">.modal-dialog>.modal-content>.modal-body").height(h4);
            $("#"+id+">.modal-dialog").css("margin",0);
            $("#"+id+">.modal-dialog>.modal-content").css("border",0);
            $("#"+id+">.modal-dialog>.modal-content").css("border-radius",0);   
        }
        //Aply changes on screen resize (example: mobile orientation)
        window.onresize=function(){
            $("#"+id+">.modal-dialog>.modal-content>.modal-body").css("height","auto");
            h1=$("#"+id+">.modal-dialog").height();
            h2=$(window).height();
            h3=$("#"+id+">.modal-dialog>.modal-content>.modal-body").height();
            h4=h2-(h1-h3);
            if($(window).width()>=768){
                if(h1>h2){
                    $("#"+id+">.modal-dialog>.modal-content>.modal-body").height(h4);
                }
                $("#"+id+">.modal-dialog").css("margin","30px auto");
                $("#"+id+">.modal-dialog>.modal-content").css("border","1px solid rgba(0,0,0,0.2)");
                $("#"+id+">.modal-dialog>.modal-content").css("border-radius",6);               
                if($("#"+id+">.modal-dialog").height()+30>h2){
                    $("#"+id+">.modal-dialog").css("margin-top","0px");
                    $("#"+id+">.modal-dialog").css("margin-bottom","0px");
                }
            }
            else{
                //Fix full-screen in mobiles
                $("#"+id+">.modal-dialog>.modal-content>.modal-body").height(h4);
                $("#"+id+">.modal-dialog").css("margin",0);
                $("#"+id+">.modal-dialog>.modal-content").css("border",0);
                $("#"+id+">.modal-dialog>.modal-content").css("border-radius",0);   
            }
        };
    });  
    //Free event listener
    $('#'+id).on('hide.bs.modal',function(){
        window.onresize=function(){};
    });  
    //Mobile haven't scrollbar, so this is touch event scrollbar implementation
    var y1=0;
    var y2=0;
    var div=$("#"+id+">.modal-dialog>.modal-content>.modal-body")[0];
    div.addEventListener("touchstart",function(event){
        y1=event.touches[0].clientY;
    });
    div.addEventListener("touchmove",function(event){
        event.preventDefault();
        y2=event.touches[0].clientY;
        var limite=div.scrollHeight-div.clientHeight;
        var diff=div.scrollTop+y1-y2;
        if(diff<0)diff=0;
        if(diff>limite)diff=limite;
        div.scrollTop=diff;
        y1=y2;
    });
    //Fix position modal, scroll to top.    
    $('html, body').scrollTop(0);
    //Show
    $("#"+id).modal('show');
}

Answer 2

EDIT: An unofficial Bootstrap Modal modification has been built to address responsive/mobile issues. This is perhaps the simplest and easiest way to remedy the problem.

There has since been a fix found in one of the issues you discussed earlier

in bootstrap-responsive.css

.modal { 
    position: fixed; 
    top: 3%; 
    right: 3%; 
    left: 3%; 
    width: auto; 
    margin: 0; 
}
.modal-body { 
    height: 60%; 
}

and in bootstrap.css

.modal-body { 
    max-height: 350px; 
    padding: 15px; 
    overflow-y: auto; 
    -webkit-overflow-scrolling: touch; 
 }

Answer 3

OK this does fix it I tried it today Sept 5-2012 but you have to be sure to check out the demo

The solution by niftylettuce in issue 2130 seems to fix modals in all mobile platforms...

9/1/12 UPDATE: The fix has been updated here: twitter bootstrap jquery plugins

here is the link to the Demo It works great heres the code I used

            title_dialog.modal();
            title_dialog.modalResponsiveFix({})
            title_dialog.touchScroll();

Answer 4

The solution by niftylettuce in issue 2130 seems to fix modals in all mobile platforms...

9/1/12 UPDATE: The fix has been updated here: twitter bootstrap jquery plugins

(the code below is older but still works)

// # Twitter Bootstrap modal responsive fix by @niftylettuce
//  * resolves #407, #1017, #1339, #2130, #3361, #3362, #4283
//   <https://github.com/twitter/bootstrap/issues/2130>
//  * built-in support for fullscreen Bootstrap Image Gallery
//    <https://github.com/blueimp/Bootstrap-Image-Gallery>

// **NOTE:** If you are using .modal-fullscreen, you will need
//  to add the following CSS to `bootstrap-image-gallery.css`:
//
//  @media (max-width: 480px) {
//    .modal-fullscreen {
//      left: 0 !important;
//      right: 0 !important;
//      margin-top: 0 !important;
//      margin-left: 0 !important;
//    }
//  }
//

var adjustModal = function($modal) {
  var top;
  if ($(window).width() <= 480) {
    if ($modal.hasClass('modal-fullscreen')) {
      if ($modal.height() >= $(window).height()) {
        top = $(window).scrollTop();
      } else {
        top = $(window).scrollTop() + ($(window).height() - $modal.height()) / 2;
      }
    } else if ($modal.height() >= $(window).height() - 10) {
      top = $(window).scrollTop() + 10;
    } else {
      top = $(window).scrollTop() + ($(window).height() - $modal.height()) / 2;
    }
  } else {
    top = '50%';
    if ($modal.hasClass('modal-fullscreen')) {
      $modal.stop().animate({
          marginTop  : -($modal.outerHeight() / 2)
        , marginLeft : -($modal.outerWidth() / 2)
        , top        : top
      }, "fast");
      return;
    }
  }
  $modal.stop().animate({ 'top': top }, "fast");
};

var show = function() {
  var $modal = $(this);
  adjustModal($modal);
};

var checkShow = function() {
  $('.modal').each(function() {
    var $modal = $(this);
    if ($modal.css('display') !== 'block') return;
    adjustModal($modal);
  });
};

var modalWindowResize = function() {
  $('.modal').not('.modal-gallery').on('show', show);
  $('.modal-gallery').on('displayed', show);
  checkShow();
};

$(modalWindowResize);
$(window).resize(modalWindowResize);
$(window).scroll(checkShow);

Answer 5

Albeit this question is quite old, some people still may stumble upon it when looking for solution to improve UX of modals on mobile phones.

I've made a lib to improve Bootrsrap modals' behavior on phones.

Bootstrap 3: https://github.com/keaukraine/bootstrap-fs-modal

Bootstrap 4: https://github.com/keaukraine/bootstrap4-fs-modal

Answer 6

We use this code to center the Bootstrap modal dialogs when they open. I haven't had any issue with them on iOS while using this but I'm not sure if it will work for Android.

$('.modal').on('show', function(e) {
    var modal = $(this);
    modal.css('margin-top', (modal.outerHeight() / 2) * -1)
         .css('margin-left', (modal.outerWidth() / 2) * -1);
    return this;
});