Build Javascript Widget

test.html

<script type="text/javascript" src="http://mywebsite.com/widgets/initial.js"></script>
<div id="mywebsite-container"></div>

widget.js

var jQuery;

if (window.jQuery === undefined || window.jQuery.fn.jquery !== '1.7.1') {
    var script_tag = document.createElement('script');
    script_tag.setAttribute("type","text/javascript");
    script_tag.setAttribute("src",
    "http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js");
    if (script_tag.readyState) {
        script_tag.onreadystatechange = function () { // For old versions of IE
            if (this.readyState == 'complete' || this.readyState == 'loaded') {
                scriptLoadHandler();
            }
        };
    } else { // Other browsers
        script_tag.onload = scriptLoadHandler;
    }
    (document.getElementsByTagName("head")[0] || document.documentElement).appendChild(script_tag);
} else {
    jQuery = window.jQuery;
    main(); //our main JS functionality
}


function scriptLoadHandler() {
    jQuery = window.jQuery.noConflict(true);

    main(); //our main JS functionality
}

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


        //setup vars
        var homeURL = 'http://mywebsite.com/';

        var css_link = $("<link>", {
            rel: "stylesheet",
            type: "text/css",
            href: baseURL + "widgets/style.css"
        });

        var $container = $('#mywebsite-container');

        //inject CSS required for widget
        css_link.appendTo('head');

        //an initial JSON request for data
        $.getJSON(homeURL + 'widgets/initial.json?callback=?', function(response) {
            $container.append(response.html);
            $container.find('input[type="text"]').each(function(idx, el) {
                $(el).val($(el).data('label'));
            });

            $container.find('input[type="button"]').click(function(e) {
                e.preventDefault();

                var itemType = $(this).parent().parents('div:first').attr('id');
                fetchItem(itemType, 1)
            });
        }, 'html');


        //Create delegates for click events.
        //Different actions for different items.
        $container.delegate('.pagination a', 'click', function(e) {
            e.preventDefault();

            var itemType = $(this).parent().parent().parent().attr('id');
            var page     = $(this).text();
            fetchItem(itemType, page);
        });

        $container.delegate('.custom-tabs a', 'click', function(e) {
            e.preventDefault();

            $('.custom-tabs').find('.custom-selected').removeClass('custom-selected');
            $('.custom-content').hide();
            $('.custom-content:eq(' + $(this).index('.custom-tabs a') + ')').show();
            $(this).parent().addClass('custom-selected');
        });

        //custom function to fetch appropriate data and replace existing HTML with response.
        function fetchItem(id, page) {
            var $form = $('#' + id).find('form');
            var endpoint = id.replace(/custom-/, '');
            var json = {
                'name' : $form.find('.name').val(),
                'location' : $form.find('.location').val(),
                'page' : page,
                'per_page' : 5
            }

            $.getJSON(homeURL + endpoint + '.json?callback=?', json, function(response) {
                $form.hide();
                $('#' + id).find('.custom-results').replaceWith(response.html);
            });
        }


    });
}