diff --git a/static/layout.js b/static/layout.js
index 516d385..766853d 100644
--- a/static/layout.js
+++ b/static/layout.js
@@ -9,3 +9,19 @@ const highlightActiveNavItem = () => {
 };
 
 highlightActiveNavItem();
+
+const getNumber = (str) => Number(str.replace("px", ""));
+
+function expandTextarea(id) {
+  document.getElementById(id).addEventListener(
+    "keyup",
+    function () {
+      this.style.overflow = "hidden";
+      this.style.height =
+        Math.max(getNumber(this.style.height), this.scrollHeight) + "px";
+    },
+    false
+  );
+}
+
+expandTextarea("prompt");