link explaining search result highlighting. fixes #762

Author: Lennart Koopmann

app/views/sidebars/searchresults.scala.html

@@ -64,6 +64,13 @@ <h4>Quick select fields</h4>
 <div class="result-highlight-control" style="display: none">
     <input type="checkbox" class="toggle-result-highlight" id="toggle-highlighting" checked /> <label for="toggle-highlighting">Highlight matches</label>
 </div>
+
+<div class="explain-result-highlight-control" style="display: none">
+    <i class="icon icon-lightbulb"></i>
+    Learn about search result highlighting
+    <a href="http://support.torch.sh/help/kb/graylog2-web-interface/search-result-highlighting" target="_blank">here</a>.
+</div>
+
 }
 
 <div id="used-indices" class="modal hide fade" tabindex="-1" role="dialog">

public/javascripts/universalsearch.js

@@ -92,23 +92,30 @@ $(document).ready(function() {
     };
     $(".messages tbody tr").each(function() {
         var ranges = $(this).data('highlight');
-        for (var field in ranges) {
-            if (! ranges.hasOwnProperty(field) ) {
-                continue;
-            }
-            var positions = ranges[field];
-            var fieldNameHash = CryptoJS.MD5(field);
-            $(".result-td-" + fieldNameHash, $(this)).each(function(){
-                var elemText = $(this).text();
-                for (var idx = positions.length - 1; idx >= 0; idx--) {
-                    var range = positions[idx];
-                    elemText = elemText.gl2_splice(range.start + range.length, "</span>");
-                    elemText = elemText.gl2_splice(range.start, '<span class="result-highlight">');
+
+        if (ranges == undefined) {
+            // Search highlighting not enabled in server.
+            $(".explain-result-highlight-control").show();
+        } else {
+            // Search highlighting is enabled in server.
+            for (var field in ranges) {
+                if (! ranges.hasOwnProperty(field) ) {
+                    continue;
                 }
-                $(this).html(elemText);
-                $(".result-highlight", $(this)).toggleClass("result-highlight-colored");
-            });
-            $(".result-highlight-control").show();
+                var positions = ranges[field];
+                var fieldNameHash = CryptoJS.MD5(field);
+                $(".result-td-" + fieldNameHash, $(this)).each(function(){
+                    var elemText = $(this).text();
+                    for (var idx = positions.length - 1; idx >= 0; idx--) {
+                        var range = positions[idx];
+                        elemText = elemText.gl2_splice(range.start + range.length, "</span>");
+                        elemText = elemText.gl2_splice(range.start, '<span class="result-highlight">');
+                    }
+                    $(this).html(elemText);
+                    $(".result-highlight", $(this)).toggleClass("result-highlight-colored");
+                });
+                $(".result-highlight-control").show();
+            }
         }
     });