/*** jQuery Drag and Scroll** Copyright (c) 2012 Ryan Naddy (ryannaddy.com)* Dual licensed under the MIT and GPL licenses:* http://www.opensource.org/licenses/mit-license.php* http://www.gnu.org/licenses/gpl.html*/(function($){  var down = false;  var prevX = 0;  var prevY = 0;  var x = 0;  var y = 0;  var px = 0;  var py = 0;  var lastPX = -1;  var lastPY = -1;  var $target = null;  var $me = null;  var $selector = "";  var settings = {    mouseButton: 3,    context: false,    selectText: false  };  $.fn.dragScroll = function(options){    settings = $.extend(settings, options);    $selector = $(this).selector;    $(this).contextmenu(function(){      return false;    }).bind("mousedown touchstart", function(e){      $me = $(this);      e = event.touches ? event.touches[0] : e;      $target = $(e.target);      $target = $target.closest($selector);      if(settings.viewPort){        if(!settings.context){          $me.contextmenu(function(){            return false;          });        }      }      if(!settings.selectText){        $me.attr('unselectable', 'on').css('user-select', 'none').on('selectstart', false);      }      $me = $me.closest($selector);      if($target && $me.attr("id") != $target.attr("id")){        return false;      }      if(e.which == settings.mouseButton || event.touches){        $me.css("cursor", "move");        down = true;      }      px = $me.scrollLeft();      py = $me.scrollTop();      x = px + e.pageX;      y = py + e.pageY;      prevX = x;      prevY = y;      return true;    }).bind("mouseup touchend", function(e){      $me = $(this);      e = event.touches ? event.touches[0] : e;      $me.css("cursor", "auto");      down = false;    }).bind("mousemove touchmove", function(e){      $me = $(this);      $me = $me.closest($selector);      e = event.touches ? event.touches[0] : e;      if((e.which == settings.mouseButton || event.touches) && down){        if(event.touches){          event.preventDefault();        }        if($target && $me.attr("id") != $target.attr("id")){          return false;        }        $me.css("cursor", "move");        px = $me.scrollLeft();        py = $me.scrollTop();        x = px + e.pageX;        y = py + e.pageY;        $me.scrollLeft(px + (-(x - prevX)));        $me.scrollTop(py + (-(y - prevY)));        prevX = x - (x - prevX);        prevY = y - (y - prevY);        if(lastPX == px)          prevX = x;        if(lastPY == py)          prevY = y;        lastPX = px;        lastPY = py;      }      return true;    });    return this;  }})(jQuery);