diff --git a/.eslintrc b/.eslintrc
index 7af1be5..9703fa9 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -14,12 +14,15 @@
     "CKEDITOR": true
   },
   "rules": {
+    // Errors.
     "block-scoped-var": 2,
-    "brace-style": [2, "stroustrup", { "allowSingleLine": true }],
+    "brace-style": [2, "stroustrup", {"allowSingleLine": true}],
     "comma-style": [2, "last"],
     "eqeqeq": [2, "smart"],
     "guard-for-in": 2,
+    "key-spacing": [2, {"beforeColon": false, "afterColon": true}],
     "no-mixed-spaces-and-tabs": 2,
+    "no-nested-ternary": 2,
     "no-reserved-keys": 2,
     "no-trailing-spaces": 2,
     "no-undef": 2,
@@ -29,6 +32,9 @@
     "space-after-keywords": [2, "always", {"checkFunctionKeyword": true}],
     "spaced-line-comment": [2, "always"],
     "strict": 2,
+    // Warnings.
+    "max-nested-callbacks": [1, 3],
+    // Disabled.
     "new-cap": 0,
     "quotes": 0,
     "camelcase": 0,
diff --git a/core/misc/states.js b/core/misc/states.js
index 6ad6029..abac1da 100644
--- a/core/misc/states.js
+++ b/core/misc/states.js
@@ -561,7 +561,15 @@
    * Bitwise AND with a third undefined state.
    */
   function ternary(a, b) {
-    return typeof a === 'undefined' ? b : (typeof b === 'undefined' ? a : a && b);
+    if (typeof a === 'undefined') {
+      return b;
+    }
+    else if (typeof b === 'undefined') {
+      return a;
+    }
+    else {
+      return a && b;
+    }
   }
 
   /**
@@ -575,7 +583,12 @@
    * Compares two values while ignoring undefined values.
    */
   function compare(a, b) {
-    return (a === b) ? (typeof a === 'undefined' ? a : true) : (typeof a === 'undefined' || typeof b === 'undefined');
+    if (a === b) {
+      return typeof a === 'undefined' ? a : true;
+    }
+    else {
+      return typeof a === 'undefined' || typeof b === 'undefined';
+    }
   }
 
 })(jQuery);
diff --git a/core/misc/tabledrag.js b/core/misc/tabledrag.js
index d984552..bb310bc 100644
--- a/core/misc/tabledrag.js
+++ b/core/misc/tabledrag.js
@@ -890,7 +890,13 @@
     var b = document.body;
 
     var windowHeight = this.windowHeight = window.innerHeight || (de.clientHeight && de.clientWidth !== 0 ? de.clientHeight : b.offsetHeight);
-    var scrollY = this.scrollY = (document.all ? (!de.scrollTop ? b.scrollTop : de.scrollTop) : (window.pageYOffset ? window.pageYOffset : window.scrollY));
+    var scrollY;
+    if (document.all) {
+      scrollY = this.scrollY = !de.scrollTop ? b.scrollTop : de.scrollTop;
+    }
+    else {
+      scrollY = this.scrollY = window.pageYOffset ? window.pageYOffset : window.scrollY;
+    }
     var trigger = this.scrollSettings.trigger;
     var delta = 0;