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copied!<p><code>obj01</code> is simply an object that inherits from a function object, you can't create functions in this way.</p> <p>The <a href="http://bclary.com/2004/11/07/#a-11.4.3" rel="nofollow noreferrer"><code>typeof</code></a> operator returns <code>"function"</code> only when its operand is by itself <em>callable</em>.</p> <p>There are only three valid ways to create function objects:</p> <p>Function declaration:</p> <pre><code>function name (/*arg, argn...*/) { } </code></pre> <p>Function expression:</p> <pre><code>var fn = function /*nameopt*/ (/*arg, argn...*/) { }; </code></pre> <p>Function constructor:</p> <pre><code>var fn = new Function("arg", "argn", "FunctionBody"); </code></pre> <p><strong>Edit:</strong> In response to your comment, <code>obj01</code> , is just an object, its prototype chain contains a function object, then <code>Function.prototype</code> and then <code>Object.prototype</code> but that doesn't make an object <em>callable</em>.</p> <p>Your object <em>is not</em> callable, functions are just objects, but they have some <em>special</em> internal properties that allow them to behave like that.</p> <p><strong>An object is callable <em>only if</em> it implements the internal <a href="http://bclary.com/2004/11/07/#a-11.2.2" rel="nofollow noreferrer"><code>[[Call]]</code></a> property</strong>.</p> <p>There are other internal properties that function objects have, like the <a href="http://bclary.com/2004/11/07/#a-11.2.2" rel="nofollow noreferrer"><code>[[Construct]]</code></a>, which is invoked when the <a href="http://bclary.com/2004/11/07/#a-11.2.2" rel="nofollow noreferrer"><code>new</code></a> operator is used, the <a href="http://bclary.com/2004/11/07/#a-11.2.2" rel="nofollow noreferrer"><code>[[Scope]]</code></a> property which stores the lexical environment where the function is executed, and more.</p> <p>If you try to invoke your object like if it were a function, you will have a <code>TypeError</code>, because when you make a <a href="http://bclary.com/2004/11/07/#a-11.2.3" rel="nofollow noreferrer">function call</a>, the object needs to have the <code>[[Call]]</code> internal property.</p> <p>Function objects need to have the above internal properties, and <em>the only way</em> that they can be constructed is by the three methods I mentioned early, you can see how internally functions objects are created <a href="http://bclary.com/2004/11/07/#a-13.2" rel="nofollow noreferrer">here</a>.</p>

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