JQuery Appear - Plugin

Appear / Dissapear Events, wenn ein Element im Viewport auftaucht / Verschwindet

Neue Version: https://github.com/morr/jquery.appear

Doku

This plugin can be used to prevent unnecessary processeing for content that is hidden or is outside of the browser viewport.

It implements a custom appear/disappear events which are fired when an element became visible/invisible in the browser viewport.

jQuery.appear

This is a total revamp of original jquery.appear plugin hosted on http://code.google.com/p/jquery-appear/

Check demo page!

This plugin can be used to prevent unnecessary processeing for content that is hidden or is outside of the browser viewport.

It implements a custom appear/disappear events which are fired when an element became visible/invisible in the browser viewport.

 $('someselector').appear(); // It supports optional hash with "force_process" and "interval" keys. Check source code for details.
 $('<div>test</div>').appear(); // It also supports raw DOM nodes wrapped in jQuery.
 $('someselector').on('appear', function(event, $all_appeared_elements) {
 // this element is now inside browser viewport
 });
 $('someselector').on('disappear', function(event, $all_disappeared_elements) {
 // this element is now outside browser viewport
 });

If you want to fire appear event for elements which are close to viewport but are not visible yet, you may add data attributes appear-top-offset and appear-left-offset to DOM nodes.

...

# appear will be fired when an element is below browser viewport for 600 or less pixels

Appear check can be forced by calling $.force_appear(). This is suitable in cases when page is in initial state (not scrolled and not resized) and when you want manually trigger appearance check.

Also this plugin provides custom jQuery filter for manual checking element appearance.

$('someselector').is(':appeared')

Version 0.3.6

/*
 * jQuery appear plugin
 *
 * Copyright (c) 2012 Andrey Sidorov
 * licensed under MIT license.
 *
 * https://github.com/morr/jquery.appear/
 *
 * Version: 0.3.6
 */
(function($) {
  var selectors = [];

  var check_binded = false;
  var check_lock = false;
  var defaults = {
    interval: 250,
    force_process: false
  };
  var $window = $(window);

  var $prior_appeared = [];

  function appeared(selector) {
    return $(selector).filter(function() {
      return $(this).is(':appeared');
    });
  }

  function process() {
    check_lock = false;
    for (var index = 0, selectorsLength = selectors.length; index < selectorsLength; index++) {
      var $appeared = appeared(selectors[index]);

      $appeared.trigger('appear', [$appeared]);

      if ($prior_appeared[index]) {
        var $disappeared = $prior_appeared[index].not($appeared);
        $disappeared.trigger('disappear', [$disappeared]);
      }
      $prior_appeared[index] = $appeared;
    }
  }

  function add_selector(selector) {
    selectors.push(selector);
    $prior_appeared.push();
  }

  // "appeared" custom filter
  $.expr[':'].appeared = function(element) {
    var $element = $(element);
    if (!$element.is(':visible')) {
      return false;
    }

    var window_left = $window.scrollLeft();
    var window_top = $window.scrollTop();
    var offset = $element.offset();
    var left = offset.left;
    var top = offset.top;

    if (top + $element.height() >= window_top &&
        top - ($element.data('appear-top-offset') || 0) <= window_top + $window.height() &&
        left + $element.width() >= window_left &&
        left - ($element.data('appear-left-offset') || 0) <= window_left + $window.width()) {
      return true;
    } else {
      return false;
    }
  };

  $.fn.extend({
    // watching for element's appearance in browser viewport
    appear: function(options) {
      var opts = $.extend({}, defaults, options || {});
      var selector = this.selector || this;
      if (!check_binded) {
        var on_check = function() {
          if (check_lock) {
            return;
          }
          check_lock = true;

          setTimeout(process, opts.interval);
        };

        $(window).scroll(on_check).resize(on_check);
        check_binded = true;
      }

      if (opts.force_process) {
        setTimeout(process, opts.interval);
      }
      add_selector(selector);
      return $(selector);
    }
  });

  $.extend({
    // force elements's appearance check
    force_appear: function() {
      if (check_binded) {
        process();
        return true;
      }
      return false;
    }
  });
})(function() {
  if (typeof module !== 'undefined') {
    // Node
    return require('jquery');
  } else {
    return jQuery;
  }
}());

Alte Version

Alte Version:

/*
 * jQuery.appear
 * http://code.google.com/p/jquery-appear/
 *
 * Copyright (c) 2009 Michael Hixson
 * Licensed under the MIT license (http://www.opensource.org/licenses/mit-license.php)
*/
(function($){$.fn.appear=function(f,o){var s=$.extend({one:true},o);return this.each(function(){var t=$(this);t.appeared=false;if(!f){t.trigger('appear',s.data);return;}var w=$(window);var c=function(){if(!t.is(':visible')){t.appeared=false;return;}var a=w.scrollLeft();var b=w.scrollTop();var o=t.offset();var x=o.left;var y=o.top;if(y+t.height()>=b&&y<=b+w.height()&&x+t.width()>=a&&x<=a+w.width()){if(!t.appeared)t.trigger('appear',s.data);}else{t.appeared=false;}};var m=function(){t.appeared=true;if(s.one){w.unbind('scroll',c);var i=$.inArray(c,$.fn.appear.checks);if(i>=0)$.fn.appear.checks.splice(i,1);}f.apply(this,arguments);};if(s.one)t.one('appear',s.data,m);else t.bind('appear',s.data,m);w.scroll(c);$.fn.appear.checks.push(c);(c)();});};$.extend($.fn.appear,{checks:[],timeout:null,checkAll:function(){var l=$.fn.appear.checks.length;if(l>0)while(l--)($.fn.appear.checks[l])();},run:function(){if($.fn.appear.timeout)clearTimeout($.fn.appear.timeout);$.fn.appear.timeout=setTimeout($.fn.appear.checkAll,20);}});$.each(['append','prepend','after','before','attr','removeAttr','addClass','removeClass','toggleClass','remove','css','show','hide'],function(i,n){var u=$.fn[n];if(u){$.fn[n]=function(){var r=u.apply(this,arguments);$.fn.appear.run();return r;}}});})(jQuery);