Put the search bar into an HTML form (#669)

This enables "Add a keyword for this search" in the contex menu for the
search field, in Firefox and other browsers.

Author: mbrubeck

src/theme/index.hbs

@@ -116,9 +116,9 @@
 
                 {{#if search_enabled}}
                 <div id="search-wrapper" class="hidden">
-                    <div id="searchbar-outer" class="searchbar-outer">
-                        <input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
-                    </div>
+                    <form id="searchbar-outer" class="searchbar-outer">
+                        <input type="search" name="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
+                    </form>
                     <div id="searchresults-outer" class="searchresults-outer hidden">
                         <div id="searchresults-header" class="searchresults-header"></div>
                         <ul id="searchresults">

src/theme/searcher/searcher.js

@@ -242,6 +242,7 @@ window.search = window.search || {};
     function init() {
         resultsoptions = window.search.resultsoptions;
         searchoptions = window.search.searchoptions;
+        searchbar_outer = window.search.searchbar_outer;
         searchindex = elasticlunr.Index.load(window.search.index);
 
         // Set up events
@@ -250,6 +251,8 @@ window.search = window.search || {};
         document.addEventListener('keydown', function(e) { globalKeyHandler(e); }, false);
         // If the user uses the browser buttons, do the same as if a reload happened
         window.onpopstate = function(e) { doSearchOrMarkFromUrl(); };
+        // Suppress "submit" events so the page doesn't reload when the user presses Enter
+        document.addEventListener('submit', function(e) { e.preventDefault(); }, false);
 
         // If reloaded, do the search or mark again, depending on the current url parameters
         doSearchOrMarkFromUrl();