Why do we need a function plugin when we write a method plugin
<p>I am a JQuery newbie and I came across this jquery plugin sample code when I was reading a Jquery book.</p>

<pre><code>//adding a function to JQuery object
jQuery.slowEach = function( array, interval, callback ) {
    if( ! array.length ) return;
    var i = 0;
    next();
    function next() {
        if( callback.call( array[i], i, array[i] ) !== false )
            if( ++i &lt; array.length )
                setTimeout( next, interval );
    }
    return array;
};

//attaching a new method .slowEach()
jQuery.fn.slowEach = function( interval, callback ) {
    return jQuery.slowEach( this, interval, callback );
};

// Show an element every half second
$('.reveal').slowEach( 500, function() {
    $(this).show();
})
</code></pre>

<p>I just want to know if it's necessary to write the function plugin when I'm writing such method plugin, and whats the significance? If not, can I write the whole thing in the jQuery.fn.slowEach method without the function plugin?</p>

<p>Thanks!</p>
