adjusted search highlight feature to accomodate multiple strings

site/public/search.php

 
   </div>
   <script>
-    let text = "<?php echo $_POST["search"]; ?>";
-    upperText = text.toUpperCase();
-    result = "<span style='color:orange'>" + upperText + "</span>";
     const collection = document.getElementsByClassName("search_term");
     for (let i = 0; i < collection.length; i++) {
+      let text = collection[i].textContent;
+      console.log(collection[i]);
+      upperText = text.toUpperCase();
+      result = "<span style='color:orange'>" + upperText + "</span>";
       collection[i].innerHTML = result;
     }
   </script>

site/solr.php

 
 function solr_search($search, $core, $sort){
 
+  // URL encode the search term
+  $search = urlencode($search);
+
   if ($sort == 'relevance'){
     // Assemble a query string to send to Solr. This uses the Solr hostname from config.env. Solr's query syntax can be found at many sites including https://lucene.apache.org/solr/guide/6_6/the-standard-query-parser.html
     $solrurl = 'http://' . $_ENV["SOLR_HOSTNAME"] . ':' . $_ENV["SOLR_PORT"] . '/solr/' . $core . '/select?q.op=OR&q=content%3A' . $search . '&wt=json';

site/text_functions.php

 <?php
 
-function highlight_search_terms($array, $search_term){
-  $replacement = "<span class='search_term'>$search_term</span>";
-  $result = str_ireplace($search_term, $replacement, $array);
+function highlight_search_terms($result, $search_term){
+  $search_array = explode(" ", $search_term);
+  foreach ($search_array as $term) {
+    $replacement = "<span class='search_term'>$term</span>";
+    $result = str_ireplace($term, $replacement, $result);
+  }
   return $result;
 }