WordPress jQuery for custom upload media metabox

    jQuery(document).ready(function($) {
        var formfield = null;
        $('#upload_image_button').click(function() {
            $('html').addClass('Image');
            formfield = $(this).prev('input').attr('name');
            formfield_id = $(this).prev('input').attr('id');
            tb_show( '', 'media-upload.php?type=image&TB_iframe=true' );
            return false;
        });

        // user inserts file into post.
        // only run custom if user started process using the above process
        // window.send_to_editor(html) is how wp normally handles the received data
        window.original_send_to_editor = window.send_to_editor;
        window.send_to_editor = function( html ) {
            var fileurl;
            if(formfield != null) {
                fileurl = $( 'img', html).attr('src');
                $( "#" + formfield_id ).val(fileurl);
                tb_remove();
                $('html').removeClass('Image');
                formfield = null;
            } else {
                window.original_send_to_editor(html);
            }
        };
    });