diff --git a/index.html b/index.html
index 19c761e..14a9257 100644
--- a/index.html
+++ b/index.html
@@ -5,6 +5,16 @@
     <link rel="stylesheet" href="fontawesome-free-5.15.3-web/css/all.css">
     <meta http-equiv="content-type" content="text/html; charset=utf-8">
     <title>Chen Yang</title>
+    <script>
+        function toggleAbstract(absId) {
+        var x = document.getElementById(absId);
+        if (x.style.display === "none") {
+            x.style.display = "block";
+        } else {
+            x.style.display = "none";
+        }
+    }
+    </script>
   </head>
 <body bgcolor="#FFFFFF">
 
