WordPress widget form function runs twice

I’m having a problem with my custom WordPress Widget I’m making. For some weird reason the form function gets ran twice, and thus, makes two Redactor textareas, but it only happends when I add the widget to a sidebar. Not when I click the save button after it has been added.

How can I do so my form function only gets ran once, or at least make the JavaScript run once.

Full widget code

http://pastebin.com/BHDJSxWX

My form function

function form($instance)
{
    $instance = wp_parse_args((array) $instance, array( 'box1' => '', 'box2' => '', 'box3' => '', 'box4' => '' ));
    $box1 = $instance['box1'];
    $box2 = $instance['box2'];
    $box3 = $instance['box3'];
    $box4 = $instance['box4'];
    $boxqty = $instance['boxqty'];


    $uniqueID = rand();
    echo "Unique ID: ".$uniqueID;

    ?>        
    <p>
        <label for="<?php echo $this->get_field_id('boxqty'); ?>">Number of blocks: (1-4)
            <input class="widefat" id="<?php echo $this->get_field_id('boxqty'); ?>" name="<?php echo $this->get_field_name('boxqty'); ?>" type="text" value="<?php echo attribute_escape($boxqty); ?>" />
        </label>
    </p>  
    <p>
        <label for="<?php echo $this->get_field_id('box1'); ?>">Box 1: 
            <textarea class="widefat redactor_content_<?php echo $uniqueID; ?>" id="box1" name="<?php echo $this->get_field_name('box1'); ?>" style="width: 600px;"><?php echo $box1; ?></textarea>
        </label>
    </p>
    <p>
        <label for="<?php echo $this->get_field_id('box2'); ?>">Box 2: 
            <textarea class="widefat redactor_content_<?php echo $uniqueID; ?>" id="<?php echo $this->get_field_id('box2'); ?>" name="<?php echo $this->get_field_name('box2'); ?>" style="width: 600px;"><?php echo $box2; ?></textarea>
        </label>
    </p>
    <p>
        <label for="<?php echo $this->get_field_id('box3'); ?>">Box 3: 
            <textarea class="widefat redactor_content_<?php echo $uniqueID; ?>" id="<?php echo $this->get_field_id('box3'); ?>" name="<?php echo $this->get_field_name('box3'); ?>" style="width: 600px;"><?php echo $box3; ?></textarea>
        </label>
    </p>
    <p>
        <label for="<?php echo $this->get_field_id('box4'); ?>">Box 4: 
            <textarea class="widefat redactor_content_<?php echo $uniqueID; ?>" id="<?php echo $this->get_field_id('box4'); ?>" name="<?php echo $this->get_field_name('box4'); ?>" style="width: 600px;"><?php echo $box4; ?></textarea>
        </label>
    </p>
    <!--Activate Redactor-->
    <script type="text/javascript">

                jQuery('.redactor_content_<?php echo $uniqueID; ?>').redactor({
                    fixed: true
                });
            console.log('Unique ID: <?php echo $uniqueID; ?>');
    </script>
    <?php
}