为下拉框增加搜索功能（select2）

Select2 ======= [![Build Status][travis-ci-image]][travis-ci-status] [][cdnjs] [][jsdelivr] Select2 is a jQuery-based replacement for select boxes. It supports searching, remote data sets, and pagination of results. To get started, checkout examples and documentation at https://select2.org/ Use cases --------- * Enhancing native selects with search. * Enhancing native selects with a better multi-select interface. * Loading data from JavaScript: easily load items via AJAX and have them searchable. * Nesting optgroups: native selects only support one level of nesting. Select2 does not have this restriction. * Tagging: ability to add new items on the fly. * Working with large, remote datasets: ability to partially load a dataset based on the search term. * Paging of large datasets: easy support for loading more pages when the results are scrolled to the end. * Templating: support for custom rendering of results and selections. Browser compatibility --------------------- * IE 8+ * Chrome 8+ * Firefox 10+ * Safari 3+ * Opera 10.6+ Usage ----- You can source Select2 directly from a CDN like [JSDliver][jsdelivr] or [CDNJS][cdnjs], [download it from this GitHub repo][releases], or use one of the integrations below. Integrations ------------ Third party developers have created plugins for platforms which allow Select2 to be integrated more natively and quickly. For many platforms, additional plugins are not required because Select2 acts as a standard `<select>` box. Plugins * [Django] - [django-autocomplete-light] - [django-easy-select2] - [django-select2] * [Drupal] - [drupal-select2] * [Meteor] - [meteor-select2] * [Ruby on Rails][ruby-on-rails] - [select2-rails] * [Wicket] - [wicketstuff-select2] * [Yii 2][yii2] - [yii2-widget-select2] * [Angularjs][angularjs] - [mdr-angular-select2] Themes - [Bootstrap 3][bootstrap3] - [select2-bootstrap-theme] - [Bootstrap 4][bootstrap4] - [select2-bootstrap4-theme] - [Flat UI][flat-ui] - [select2-flat-theme] - [Metro UI][metro-ui] - [select2-metro] Missing an integration? Modify this `README` and make a pull request back here to Select2 on GitHub. Internationalization (i18n) --------------------------- Select2 supports multiple languages by simply including the right language JS file (`dist/js/i18n/it.js`, `dist/js/i18n/nl.js`, etc.) after `dist/js/select2.js`. Missing a language? Just copy `src/js/select2/i18n/en.js`, translate it, and make a pull request back to Select2 here on GitHub. Documentation ------------- The documentation for Select2 is available [through GitHub Pages][documentation] and is located within the [separate `select2/docs` repository][documentation-repository]. Community --------- You can find out about the different ways to get in touch with the Select2 community at the [Select2 community page][community]. Copyright and license --------------------- The license is available within the repository in the [LICENSE][license] file. [cdnjs]: http://www.cdnjs.com/libraries/select2 [community]: https://select2.org/getting-help [documentation]: https://select2.org [documentation-repository]: https://github.com/select2/docs [freenode]: https://freenode.net/ [jsdelivr]: https://www.jsdelivr.com/package/npm/select2 [license]: LICENSE.md [releases]: https://github.com/select2/select2/releases [travis-ci-image]: https://img.shields.io/travis/select2/select2/master.svg [travis-ci-status]: https://travis-ci.org/select2/select2 [angularjs]: https://angularjs.org/ [bootstrap3]: https://getbootstrap.com/ [bootstrap4]: https://getbootstrap.com/ [django]: https://www.djangoproject.com/ [django-autocomplete-light]: https://github.com/yourlabs/django-autocomplete-light [django-easy-select2]: https://github.com/asyncee/django-easy-select2 [django-select2]: https://github.com/applegrew/django-select2 [drupal]: https://www.drupal.org/ [drupal-select2]: https://www.drupal.org/project/select2 [flat-ui]: http://designmodo.github.io/Flat-UI/ [mdr-angular-select2]: https://github.com/modulr/mdr-angular-select2 [meteor]: https://www.meteor.com/ [meteor-select2]: https://github.com/nate-strauser/meteor-select2 [metro-ui]: http://metroui.org.ua/ [select2-metro]: http://metroui.org.ua/select2.html [ruby-on-rails]: http://rubyonrails.org/ [select2-bootstrap-theme]: https://github.com/select2/select2-bootstrap-theme [select2-bootstrap4-theme]: https://github.com/ttskch/select2-bootstrap4-theme [select2-flat-theme]: https://github.com/techhysahil/select2-Flat_Theme [select2-rails]: https://github.com/argerim/select2-rails [vue.js]: http://vuejs.org/ [select2-vue]: http://vuejs.org/examples/select2.html [wicket]: https://wicket.apache.org/ [wicketstuff-select2]: https://github.com/wicketstuff/core/tree/master/select2-parent [yii2]: http://www.yiiframework.com/ [yii2-widget-select2]: https://github.com/kartik-v/yii2-widget-select2