Changed all code to strict mode (`'use strict'`)

src/js/ContextMenu.js

@@ -1,3 +1,5 @@
+'use strict';
+
 var util = require('./util');
 
 /**

src/js/Highlighter.js

@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * The highlighter can highlight/unhighlight a node, and
  * animate the visibility of a context menu.

src/js/History.js

@@ -1,3 +1,5 @@
+'use strict';
+
 var util = require('./util');
 
 /**

src/js/JSONEditor.js

@@ -1,3 +1,5 @@
+'use strict';
+
 var Ajv;
 try {
   Ajv = require('ajv');

src/js/ModeSwitcher.js

@@ -1,3 +1,5 @@
+'use strict';
+
 var ContextMenu = require('./ContextMenu');
 
 /**

src/js/Node.js

@@ -1,3 +1,5 @@
+'use strict';
+
 var naturalSort = require('javascript-natural-sort');
 var ContextMenu = require('./ContextMenu');
 var appendNodeFactory = require('./appendNodeFactory');

src/js/SearchBox.js

@@ -1,3 +1,5 @@
+'use strict';
+
 /**
  * @constructor SearchBox
  * Create a search box in given HTML container

src/js/appendNodeFactory.js

@@ -1,3 +1,5 @@
+'use strict';
+
 var util = require('./util');
 var ContextMenu = require('./ContextMenu');
 

src/js/textmode.js

@@ -1,3 +1,5 @@
+'use strict';
+
 var ace;
 try {
   ace = require('./ace');

src/js/treemode.js

@@ -1,3 +1,6 @@
+'use strict';
+
+
 var Highlighter = require('./Highlighter');
 var History = require('./History');
 var SearchBox = require('./SearchBox');

src/js/util.js

@@ -1,3 +1,5 @@
+'use strict';
+
 var jsonlint = require('./assets/jsonlint/jsonlint');
 
 /**