diff --git a/src/js/page.js b/src/js/page.js
index f39c6a5..57fe14a 100644
--- a/src/js/page.js
+++ b/src/js/page.js
@@ -9,15 +9,21 @@ document.addEventListener("DOMContentLoaded", function() {
 
   // let has_one_active_toc = false
   let current_selected_toc = null
+  let current_intersectiong_entry = null
   const observer = new window.IntersectionObserver(entries => {
     entries.forEach(entry => {
       console.log('observe')
       // Add 'active' class if observation target is inside viewport
-      // console.log(entry.isIntersecting)
+      // console.log(entry)
       // console.log(entry.intersectionRatio)
       if (entry.isIntersecting) {
-        // has_one_active_toc = true
-        console.log(entry, 'active')
+        console.log('entry', entry)
+        console.log('current', current_intersectiong_entry)
+        if (first_intersectiong_section !== null && current_intersectiong_entry.isIntersecting) {
+          console.log('should stop')
+        }
+        current_intersectiong_entry = entry
+        // console.log(entry, 'active')
         let res = findCorrespondingTocTitle(entry.target)
         if (typeof res !== 'undefined' && (current_selected_toc === null || current_selected_toc !== res)) {
           // console.log('here')
diff --git a/static/js/page.js b/static/js/page.js
index c0525c1..731adcb 100644
--- a/static/js/page.js
+++ b/static/js/page.js
@@ -1 +1 @@
-function findCorrespondingTocTitle(n){return[...document.querySelectorAll("#toc li a")].find(e=>e.href.substring(e.href.indexOf("#"))==="#"+n.id)}document.addEventListener("DOMContentLoaded",function(){document.getElementById("navbar").clientHeight,document.getElementById("toc");var e=document.querySelectorAll("#toc li a");document.getElementById("page-content");let t=null;const n=new window.IntersectionObserver(e=>{e.forEach(n=>{if(console.log("observe"),n.isIntersecting){console.log(n,"active");let e=findCorrespondingTocTitle(n.target);void 0===e||null!==t&&t===e||(null!==t&&t.parentElement.classList.remove("bg-blue-800"),t=e),e.parentElement.classList.add("bg-blue-800")}})},{root:null,threshold:.1});var o=[];[...e].forEach(e=>{o.push(e.href.substring(e.href.indexOf("#")))});const l=document.querySelectorAll(o.join(","));l.forEach(e=>{n.observe(e)})});
\ No newline at end of file
+function findCorrespondingTocTitle(n){return[...document.querySelectorAll("#toc li a")].find(e=>e.href.substring(e.href.indexOf("#"))==="#"+n.id)}document.addEventListener("DOMContentLoaded",function(){document.getElementById("navbar").clientHeight,document.getElementById("toc");var e=document.querySelectorAll("#toc li a");document.getElementById("page-content");let t=null,o=null;const n=new window.IntersectionObserver(e=>{e.forEach(n=>{if(console.log("observe"),n.isIntersecting){console.log("entry",n),console.log("current",o),null!==first_intersectiong_section&&o.isIntersecting&&console.log("should stop");let e=findCorrespondingTocTitle((o=n).target);void 0===e||null!==t&&t===e||(null!==t&&t.parentElement.classList.remove("bg-blue-800"),t=e),e.parentElement.classList.add("bg-blue-800")}})},{root:null,threshold:.1});var l=[];[...e].forEach(e=>{l.push(e.href.substring(e.href.indexOf("#")))});const r=document.querySelectorAll(l.join(","));r.forEach(e=>{n.observe(e)})});
\ No newline at end of file