diff --git a/html/document.js b/html/document.js
index c507429..9819187 100644
--- a/html/document.js
+++ b/html/document.js
@@ -259,6 +259,12 @@ app = new Vue({
 			this.diff = true;
 
 			document.activeElement = null;
+		},
+		calcOverflow(){
+			const { loading,output } = this;
+			const hidden = !!(loading || output);
+			const el = document.documentElement;
+			el.setAttribute('data-no-scroll',hidden);
 		}
 	},
 	computed: {
@@ -278,12 +284,14 @@ app = new Vue({
 			handler(){
 				this._louvre();
 			}
-		}
+		},
+		loading:'calcOverflow',
+		output:'calcOverflow',
 	}
 });
 
 
-
+app.calcOverflow();
 
 setTimeout(_=>{
 
diff --git a/html/document.less b/html/document.less
index d9eeed0..0cd80ba 100644
--- a/html/document.less
+++ b/html/document.less
@@ -223,6 +223,9 @@ input[type="range"]{
 } */
 h1{
 
+}
+html[data-no-scroll="true"]{
+    overflow: hidden;
 }
 .ui-shadow{
     position: fixed;
@@ -233,6 +236,8 @@ h1{
     z-index:1;
     background:rgba(0,0,0,.5);
     overflow: auto;
+    overflow-y: scroll;
+    overscroll-behavior: contain;
 }
 .output-box{
     background:#FFF;