Polymer get element by id from shadow root

问题

I am not able to get an element by id that is in the shadow root. It will return nil. Here is the code. It is written in clojurescript.

    (p/defpolymer :query-component {:imports  ["components/polymer/polymer.html"]
                            :style    ".query-container
                             {margin: 20px;
                             display: inline-block;}"
                            :template [[:div.query-container
                                        [:div
                                         [:h4 {:style "display: inline-block;"} "Current Query"]
                                         [:button {:style    "float: right; margin-top: 10px;"
                                                   :on-click "{{runQuery}}"} "Run Query"]]
                                        [:span "{{query.name}}"]
                                        [:div#inputs]
                                        ;(cljs.reader/read-string "[:input.search-box {:type \"text\", :placeholder \"Country name\"}] ")
                                        ]]
                            :spec     {:publish      {:query {:value ""}}
                                       :runQuery     (fn []
                                                         (this-as this
                                                                  (println (:query (js->clj (.-query this) :keywordize-keys true)))))
                                       :queryChanged (fn []
                                                         (this-as this
                                                                  (let [query (js->clj (.-query this) :keywordize-keys true)
                                                                        inputs (:inputs query)]
                                                                       )
                                                                  (.log js/console (.getElementById js/document "#inputs"))
                                                                  ))}})

As you can see I am trying to get the element by the id "inputs", however, it returns null. http://i.stack.imgur.com/GHMw7.png The div is in there, but I am not able to get it by its id. Is there a reason for this and is there a way to get it by its id? It was my understanding that get elementbyid will search through the shadow roots by apparently not..

EDIT: I found the answer by just fiddling around with the name of the shadow root as a property of an element!

    (p/defpolymer :query-component {:imports  ["components/polymer/polymer.html"]
                            :style    ".query-container
                             {margin: 20px;
                             display: inline-block;}"
                            :template [[:div.query-container
                                        [:div
                                         [:h4 {:style "display: inline-block;"} "Current Query"]
                                         [:button {:style    "float: right; margin-top: 10px;"
                                                   :on-click "{{runQuery}}"} "Run Query"]]
                                        [:span "{{query.name}}"]
                                        [:div#inputs]
                                        ;(cljs.reader/read-string "[:input.search-box {:type \"text\", :placeholder \"Country name\"}] ")
                                        ]]
                            :spec     {:publish      {:query {:value ""}}
                                       :runQuery     (fn []
                                                         (this-as this
                                                                  (println (:query (js->clj (.-query this) :keywordize-keys true)))))
                                       :queryChanged (fn []
                                                         (this-as this
                                                                  (let [query (js->clj (.-query this) :keywordize-keys true)
                                                                        inputs (:inputs query)
                                                                        shadow-root (.-shadowRoot this)
                                                                        input-div (.getElementById shadow-root "inputs")]
                                                                       (set! (.-innerHTML input-div) "<span>Shadow DOM</span>"))))}})

That is the working code. The shadow root is a property on your element and it is name "shadowRoot".

回答1:

It was my understanding that getElementById will search through the shadow roots but apparently not.

None of the query methods on document will search through shadow roots, this is part of what makes them shadowy.

An exception to this rule is if you use querySelector[All] and a selector that specifically pierces shadow-roots, i.e. uses /deep/ or ::shadow).

来源：https://stackoverflow.com/questions/25043786/polymer-get-element-by-id-from-shadow-root