HTML/CSS Beautifier formats malformed HTML and CSS without validation errors

[baixiangcpp]

Summary

HTML/CSS Beautifier formats structurally malformed input and reports completion instead of surfacing a syntax error. The page guidance says broken markup and CSS syntax issues should block formatting.

Affected route: https://byteflow.tools/en/html-css-beautifier

Reproduction: CSS

1. Select CSS mode.

2. Enter:

   body{color:red;
   

3. Click Format CSS.

Expected: a CSS syntax error and no valid-looking output.

Actual: the status says Format CSS completed. and output is:

   body {
     color: red;

The missing closing brace is not reported.

Reproduction: HTML

1. Select HTML mode.

2. Enter:

   <div><p>test</div>
   

3. Click Format HTML.

Expected: a malformed-nesting error.

Actual: the status says Format HTML completed. and output remains malformed:

   <div>
     <p>test
   </div>

Environment

• Browser: Chrome via cloud browser
• Tested: 2026-08-18