diff --git a/demo/browser-exports.mjs b/demo/browser-exports.mjs
index 42adabcb..3ed596ca 100644
--- a/demo/browser-exports.mjs
+++ b/demo/browser-exports.mjs
@@ -2,6 +2,7 @@
 
 export { applyFixes, getVersion } from "markdownlint";
 export { lint as lintSync } from "markdownlint/sync";
+export { frontMatterRe } from "markdownlint/helpers";
 export { compile, parse, postprocess, preprocess } from "micromark";
 export { directive, directiveHtml } from "micromark-extension-directive";
 export { gfmAutolinkLiteral, gfmAutolinkLiteralHtml } from "micromark-extension-gfm-autolink-literal";
diff --git a/demo/default.js b/demo/default.js
index 1f58347d..8f68a027 100644
--- a/demo/default.js
+++ b/demo/default.js
@@ -49,6 +49,7 @@
 
   // Renders Markdown to HTML
   function render(markdown) {
+    markdown = markdown.replace(markdownlint.frontMatterRe, "");
     const match = /^\?renderer=([a-z-]+)$/.exec(globalThis.location.search);
     const renderer = match ? match[1] : "micromark";
     if (renderer === "markdown-it") {