Make route button inactive if no start/destination entered

static/app.js

@@ -581,6 +581,7 @@
         routeListEl.innerHTML = "";
         fromInput.value = "";
         toInput.value = "";
+        updateRouteBtn();
         fetchRepeaters();
     }
 
@@ -862,6 +863,12 @@
         }
     });
 
+    function updateRouteBtn() {
+        routeBtn.disabled = !fromInput.value.trim() || !toInput.value.trim();
+    }
+    fromInput.addEventListener("input", updateRouteBtn);
+    toInput.addEventListener("input", updateRouteBtn);
+
     routeBtn.addEventListener("click", findRoute);
     clearBtn.addEventListener("click", clearRoute);
 

static/index.html

@@ -44,7 +44,7 @@
             <ul class="autocomplete-list" id="ac-to"></ul>
         </div>
         <div class="controls-row route-row">
-            <button id="route-btn">Route</button>
+            <button id="route-btn" disabled>Route</button>
             <button id="clear-btn">Clear</button>
         </div>
         <div class="controls-row route-row corridor-row" id="corridor-row" style="display:none">