Nu HTML Validator

A standalone HTML validation tool using the Nu Html Checker (vnu.jar). Validate HTML files and folders with ease.

Requirements

Supported OS

Windows 10 / Windows 11 (64-bit)

Java Runtime Environment (JRE)

Java must be installed on your system to run this tool.

Alternative: Oracle JDK 25
Download: https://www.oracle.com/java/technologies/downloads/#jdk25-windows

Verify Installation

After installing Java, open a command prompt or PowerShell and run:

java -version

If version information is displayed, the installation was successful.

Setup

1. Download and extract the files
2. Ensure both files are in the same folder:
   • nu_html_validator.exe
   • vnu.jar
3. No additional steps required

Usage

Validate a Single HTML File

Drag and drop an HTML file onto nu_html_validator.exe.

Validate Multiple HTML Files

Select multiple HTML files and drag them onto nu_html_validator.exe.

Validate All HTML Files in a Folder

Drag and drop a folder onto nu_html_validator.exe.
All .html and .htm files in the folder and its subfolders will be automatically validated.

Understanding the Output

The validator displays:

• Number of files found
• Validation results for each file
• Errors and warnings (if any)
• Summary of total files, files with errors, and files passed

Sample Output

HTML Validator - Nu Html Checker
================================================================================
Using vnu.jar: C:\path\to\vnu.jar

Found 5 HTML file(s)

================================================================================
Validating: C:\example\index.html
================================================================================

No errors or warnings found.

================================================================================
Validation Complete
================================================================================
Total files: 5
Files with errors/warnings: 0
Files passed: 5

Press Enter to exit...

Error Types

Error

Critical issues that violate HTML standards. These should be fixed.

Warning

Non-critical issues or use of deprecated features. These may not affect functionality but should be reviewed.

Troubleshooting

Error: Java is not installed or not in PATH

Solution: Install Java Runtime Environment (see Requirements section)

Error: vnu.jar not found

Solution: Ensure vnu.jar is in the same folder as nu_html_validator.exe

No HTML files found

Possible causes:

• The folder contains no .html or .htm files
• Files have incorrect extensions

Distribution

You may freely distribute this tool along with vnu.jar. Please include this README file when distributing.

Technical Specifications

Supported File Extensions

• .html
• .htm

vnu.jar Search Order

1. Same folder as nu_html_validator.exe (highest priority)
2. Default path: C:\Users\[username]\Tools\vnu\vnu.jar

Character Encoding

Properly handles UTF-8 encoded files and displays international characters correctly.

License

Nu HTML Validator Wrapper: Created for personal and educational use

Nu Html Checker (vnu.jar): MIT License