show if homeserver URL is invalid

src/page/SignIn/SignIn.svelte

@@ -4,6 +4,13 @@
     import AccountStore from '../../store/AccountStore';
 
     let homeserver = AccountStore.getState().homeserver;
+    let homeserverValid = homeserver.match(/.+(\..+){1,}/gm) !== null;
+    
+    const updStore = () => {
+        AccountStore.dispatch({ type: 'setHomeserver', homeserver });
+        console.log(AccountStore.getState().homeserver);
+        homeserverValid = homeserver.match(/.+(\..+){1,}/gm) !== null;
+    }
 </script>
 
 <div class={style.root}>
@@ -11,7 +18,7 @@
     <p style="text-align:center">
         To continue, you must choose a homeserver<br/>
 
-        <input type='text' value={homeserver} style="background: #ffeeee06">
+        <input type='text' bind:value={homeserver} on:input={updStore} style="background: #ffeeee06">
         <br/>
 
         <button>What is a homeserver?</button>
@@ -19,5 +26,11 @@
     </p>
     <p style="text-align:center">
         <button class="primary">Choose {homeserver}</button>
+        {#if (!homeserverValid)}
+            <br/>
+            <span style='font-size:10pt;color:darkred'>
+                Error: Invalid URL
+            </span>
+        {/if}
     </p>
 </div>