How to get the image url in the input box from media library?

I have added a post meta to upload image using wordpress media uploader. Looks like it’s a javascript work. I am no good in javascript. I took the js from here:

Here is the js code:

jQuery(document).ready(function($){

    // Instantiates the variable that holds the media library frame.
    var meta_image_frame;

    // Runs when the image button is clicked.
    $('#meta-image-button').click(function(e){

        // Prevents the default action from occuring.
        e.preventDefault();

        // If the frame already exists, re-open it.
        if ( meta_image_frame ) {
            wp.media.editor.open();
            return;
        }

        // Sets up the media library frame
        meta_image_frame = wp.media.frames.meta_image_frame = wp.media({
            title: meta_image.title,
            button: { text:  meta_image.button },
            library: { type: 'image' }
        });

        // Runs when an image is selected.
        meta_image_frame.on('select', function(){

            //Grabs the attachment selection and creates a JSON representation of the model.
            var media_attachment = meta_image_frame.state().get('selection').first().toJSON();

            // Sends the attachment URL to our custom image input field.
            $('#meta-image').val(media_attachment.url);
        });

        // Opens the media library frame.
        wp.media.editor.open();
    });
});

I have an input box with id #meta-image. But it does not return the img url there. Instead, it puts the image url inside the main post editor. Any idea how can I get this to work?

I have solved this by changing wp.media.editor.open() to meta_image_frame.open().

It’s now working fine. But I am not sure what was the error before.