ignore empty lines in installation form

scripts.js

@@ -9,6 +9,11 @@ function updateForm() {
 	instances = document.getElementById("instance-input").value.split("\n");
 
 	for (const instance of instances) {
+		// skip empty lines
+		if (!instance.trim()) {
+			continue;
+		}
+
 		let input = document.createElement("input");
 		input.type = "hidden";
 		input.name = "instances[]";