Make frequency slider again

popup/popup.html

@@ -42,10 +42,10 @@
         </div>
         <div class="row">
             <div class="col">
-                <label for="frequency" class="form-label">Frequency (minutes)</label>
+                <label for="frequency">Check frequency<br>(every <span id="frequency_info">N</span> minutes)</label>
             </div>
             <div class="col">
-                <input type="number" class="form-control" id="frequency" placeholder="minutes">
+                <input type="range" id="frequency" name="frequency" min="1" max="15" step="1">
             </div>
         </div>
         <div class="row">