diff --git a/jquery.appear.js b/jquery.appear.js
index ff0b764..8c877cf 100644
--- a/jquery.appear.js
+++ b/jquery.appear.js
@@ -1,3 +1,6 @@
+/*jslint browser:true, devel:true, sloppy:true */
+/*global jQuery */
+
 /*
  * jQuery appear plugin
  *
@@ -8,94 +11,108 @@
  *
  * Version: 0.3.3
  */
-(function($) {
-  var selectors = [];
+(function ($) {
+    var selectors = [],
+        check_binded = false,
+        check_lock = false,
+        defaults = {
+            "interval": 250,
+            "force_process": false
+        },
+        $window = $(window),
+        $prior_appeared;
 
-  var check_binded = false;
-  var check_lock = false;
-  var defaults = {
-    interval: 250,
-    force_process: false
-  }
-  var $window = $(window);
+    function process() {
+        var index,
+            length = selectors.length,
+            $appeared,
+            $disappeared;
 
-  var $prior_appeared;
+        check_lock = false;
+        
+        function isAppeared() {
+            return $(this).is(':appeared');
+        }
 
-  function process() {
-    check_lock = false;
-    for (var index = 0; index < selectors.length; index++) {
-      var $appeared = $(selectors[index]).filter(function() {
-        return $(this).is(':appeared');
-      });
+        for (index = 0; index < length; index += 1) {
+            $appeared = $(selectors[index]).filter(isAppeared);
 
-      $appeared.trigger('appear', [$appeared]);
+            $appeared.trigger('appear', [$appeared]);
 
-      if ($prior_appeared) {
-        var $disappeared = $prior_appeared.not($appeared);
-        $disappeared.trigger('disappear', [$disappeared]);
-      }
-      $prior_appeared = $appeared;
+            if ($prior_appeared) {
+                $disappeared = $prior_appeared.not($appeared);
+                $disappeared.trigger('disappear', [$disappeared]);
+            }
+            $prior_appeared = $appeared;
+        }
     }
-  }
 
-  // "appeared" custom filter
-  $.expr[':']['appeared'] = function(element) {
-    var $element = $(element);
-    if (!$element.is(':visible')) {
-      return false;
-    }
+    // "appeared" custom filter
+    $.expr[':'].appeared = function (element) {
+        var $element = $(element),
+            window_left,
+            window_top,
+            offset,
+            left,
+            top;
 
-    var window_left = $window.scrollLeft();
-    var window_top = $window.scrollTop();
-    var offset = $element.offset();
-    var left = offset.left;
-    var top = offset.top;
+        if (!$element.is(':visible')) {
+            return false;
+        }
+        window_left = $window.scrollLeft();
+        window_top = $window.scrollTop();
+        offset = $element.offset();
+        left = offset.left;
+        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;
-    }
-  }
+        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;
+    $.fn.extend({
+        // watching for element's appearance in browser viewport
+        "appear": function (options) {
+            var opts,
+                selector,
+                on_check;
+            opts = $.extend({}, defaults, options || {});
+            selector = this.selector || this;
+            if (!check_binded) {
+                on_check = function () {
+                    if (check_lock) {
+                        return;
+                    }
+                    check_lock = true;
 
-          setTimeout(process, opts.interval);
-        };
+                    setTimeout(process, opts.interval);
+                };
 
-        $(window).scroll(on_check).resize(on_check);
-        check_binded = true;
-      }
+                $(window).scroll(on_check).resize(on_check);
+                check_binded = true;
+            }
 
-      if (opts.force_process) {
-        setTimeout(process, opts.interval);
-      }
-      selectors.push(selector);
-      return $(selector);
-    }
-  });
+            if (opts.force_process) {
+                setTimeout(process, opts.interval);
+            }
+            selectors.push(selector);
+            return $(selector);
+        }
+    });
 
-  $.extend({
-    // force elements's appearance check
-    force_appear: function() {
-      if (check_binded) {
-        process();
-        return true;
-      };
-      return false;
-    }
-  });
-})(jQuery);
+    $.extend({
+        // force elements's appearance check
+        "force_appear": function () {
+            if (check_binded) {
+                process();
+                return true;
+            }
+            return false;
+        }
+    });
+}(jQuery));
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