only can click submit if video is valid, and clears after submit

src/components/Channel_Add.vue

@@ -45,7 +45,7 @@
                         </p>
                         <button type="button"
                             class="button input-group" style="max-height:50px; max-width:100px; float: right;"
-                            @click="Submit">Submit</button>
+                            v-if="Valid" @click="Submit">Submit</button>
                     </div>
                     <div class="medium-2 cell"></div>
                     <div class="input-group medium-2 cell">
@@ -154,6 +154,11 @@ export default Vue.extend({
 
             // Hide the bars and erase internal state.
             this.Expanded = false;
+            this.clear();
+        },
+
+        // Clears the contents of the add channel field
+        clear() : void {
             this.Title = "";
             this.Description = "";
             this.ID = "";
@@ -203,8 +208,13 @@ export default Vue.extend({
                 this.ID = this.ID.replace(ytchurl, "");
 
             // Check if what remains looks like a youtube channel ID.
-            if (this.ID.length != "UCyS4xQE6DK4_p3qXQwJQAyA".length)
+            if (this.ID.length != "UCyS4xQE6DK4_p3qXQwJQAyA".length){
-                return;
+                this.Title = "";
+                this.Description = "";
+                this.ID = "";
+                this.Thumbnail = "";
+                this.Valid = false;
+            }
 
             // Get channel metadata.
             const API = 'https://www.googleapis.com/youtube/v3/channels?';
@@ -215,6 +225,7 @@ export default Vue.extend({
                 this.Description = _.truncate(resp.data.items[0].snippet.description, {length: 70});
                 this.Title = resp.data.items[0].snippet.title;
                 this.Thumbnail = resp.data.items[0].snippet.thumbnails.high.url;
+                this.Valid = true;
             })
             .catch(function (error) {
                 console.log(error);