```js
var Ext = Ext || {};
Ext.extend = function(subclass, superclass) {
  superclass = subclass;
  subclass = function() { superclass.apply(this, arguments); };

  var F = function() {};
  F.prototype = superclass.prototype;
  subclass.prototype = new F();

  subclass.extend = function(o) { return Ext.extend(subclass, o); };
};

var Ext = Ext || {};
Ext.extend = function(subclass, superclass) {
  superclass = subclass;
  subclass = function() { superclass.apply(this, arguments); };

  var F = function() {};
  F.prototype = superclass.prototype;
  subclass.prototype = new F();

  subclass.extend = function(o) { return Ext.extend(subclass, o); };
};
```
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```
```ctags
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prototype	__DIR__/blowup.js	/prototype/;"	v	lineno:8	namespace:Ext.extend.subclass
extend	__DIR__/blowup.js	/extend/;"	f	lineno:10	namespace:Ext.extend.subclass	type:void function(?)
o	__DIR__/blowup.js	/o/;"	v	lineno:10	namespace:Ext.extend.subclass.extend
subclass	__DIR__/blowup.js	/subclass/;"	f	lineno:14	namespace:Ext.extend	type:void function()
superclass	__DIR__/blowup.js	/superclass/;"	f	lineno:14	namespace:Ext.extend	type:void function()
F	__DIR__/blowup.js	/F/;"	f	lineno:18	namespace:Ext.extend	type:void function()
prototype	__DIR__/blowup.js	/prototype/;"	v	lineno:19	namespace:Ext.extend.F
```