I found a solution that's working here:
http://jsfiddle.net/9xr5af00/
(next step: CSS stuff)
--------------------------------------------
En date de : Mar 21.6.16, Pascal BASTIEN <pbasnews-xwiki(a)yahoo.fr> a écrit :
 Objet: need help about JS/webjar integration
 À: "XWiki Users" <users(a)xwiki.org>
 Date: Mardi 21 juin 2016, 11h53
 Hi,
 about 
http://jira.xwiki.org/browse/XWIKI-13470
 I can use 
https://silviomoreto.github.io/bootstrap-select/ JS if
 I copy js content in a JSX object between this stuff:
 require(['jquery'], function ($) {
 });
 To PullRequesting I need to writing cleaner code: I mean
 "use RequireJS and WebJars API to load and use the
 bootstrap-select widget"
 Then I copied bootstrap-select JAR to WEB-INF/lib and add
 add this 2 lines in ./skins/flamingo/javascript.vm:
 (bootstrap-select requires jQuery v1.8.0+, Bootstrap’s
 dropdown.js component, and Bootstrap's CSS.)
 ------------------------------
 require.config({
   paths: {
     'jquery':
 '#removeJsSuffix($services.webjars.url("jquery",
 "jquery${jsExtension}"))',
     'bootstrap':
 '#removeJsSuffix($services.webjars.url("bootstrap",
 "js/bootstrap${jsExtension}"))',
     'bootstrap-select':
'#removeJsSuffix($services.webjars.url("bootstrap-select/1.10.0/js/bootstrap-select.js"))',
 <cut>
  shim: {
     'bootstrap' : ['jquery'],
     'bootstrap-select' : ['jquery'],
 (or 'bootstrap-select' : ['jquery', 'bootstrap'],
 <cut>
 I tested with minify version too with
 shim: {
     'bootstrap' : ['jquery'],
     'bootstrap-select': {
       deps: ['jquery', 'bootstrap'],
       exports: 'bootstrap-select'
       },
 
http://requirejs.org/docs/api.html#config-shim
 ------------------------------
 Unfortunaly when I use the webjar with this config,
 bootstrap-select doesn't work.
 Do I miss something?
 (Source Page generated contain:
 'bootstrap-select':
 '/xwiki/webjars/wiki%3Axwiki/bootstrap-select/1.10.0/js/bootstrap-select.js?r=1',
 and my browser can read bootstrap-select.js content at this
 URL.)
 (I tried to enables this too:
 pluginsToDisable = ['collapse', 'dropdown', 'modal',
 'tooltip', 'tab', 'popover'] => pluginsToDisable =
 ['collapse',  'modal', 'tooltip', 'tab',
'popover']
 Any help are welcome.
 Thxs
 Pascal B