frontend: Add input-dispatch event listener only when destination exists

frontend/src/main.ts

@@ -11,8 +11,10 @@ function onInputHandler(event: Event) {
 }
 
 window.addEventListener("load", () => {
+	if (document.getElementById('preview')) {
 		for (let el of document.getElementsByClassName('input-dispatch')) {
 			console.log(el);
 			el.addEventListener('input', onInputHandler);
 		}
+	}
 });