button _also_ does sumbit??

templates/party.html

@@ -125,19 +125,16 @@
             return data;
         }).then(set_state);
     }
+
     function return_handler(e) {
         e.preventDefault();
+        console.log("wario");
         let code = document.getElementById("student_number").value;
         console.log(code);
         scan_ticket(code);
         document.getElementById("student_number").value = "";
     }
 
-    function button_click_handler() {
-        let code = document.getElementById("student_number").value;
-        scan_ticket(code);
-    }
-    document.getElementById("add_student").addEventListener("click", button_click_handler);
     document.getElementById("student_number_wrapper").addEventListener("submit", return_handler);
     document.getElementById("start_scan_btn").addEventListener('click', start_scanning);
 
@@ -255,5 +252,10 @@
 
     document.getElementById("file-selector-button").addEventListener("click", upload_csv);
 
+
+    let elem = document.getElementById("student_number");
+    elem.focus();
+    elem.select();
+
 </script>
 {% endblock %}