Syntax Highlighting PowerShell Code in HTML - With a PowerShell Script

Scripting
Published Jan 18, 2010 Updated Jan 4, 2026

When you are publishing PowerShell code on the web, you soon discover that it looks much nicer with syntax highlighting - as did I. There are several ways to add syntax highlighting to your blog or web site, most of which rely on external (Wordpress) plugins or JavaScript on the page. I do not like that approach too much. I prefer to have the syntax highlighting embedded in the HTML code. That way I have full control over the appearance (and the highlighting also works in the RSS feed). The logical solution is to use a script that embeds HTML coloring tags directly into the script.

Highlight-Syntax.ps1

My script Highlight-Syntax.ps1 is a much stripped down and slightly changed version of Lee Holmes’ Set-ClipboardScript.ps1 - thank you for making it available, Lee!

You call Highlight-Syntax.ps1 with the name of a PowerShell script which it parses and then generates an HTML file with a colorized version of that script. If you input Get-AppVPackageDependencies.ps1 you will get Get-AppVPackageDependencies.ps1.html. That is it. The code in the HTML file can then easily be pasted into your favorite blog editor.

Highlight-Syntax.ps1 does not create fully-featured HTML files with head and body tags. That is by design. It simply takes your code and adds color information to it.

The Code - And a Sample

Here is the script which doubles as a sample of what its output looks like.

#
# Original Author: Lee Holmes, http://www.leeholmes.com/blog/MorePowerShellSyntaxHighlighting.aspx
#
# Modified by: Helge Klein, https://helgeklein.com/
#

#
# Syntax highlights a PowerShell script.
#
# Usage: Supply the script to syntax hightligh as first and only parameter
#
# Output: Copy of original script with extension ".html"
#
# Example: .\Highlight-Syntax.ps1 .\Get-AppVPackageDependencies.ps1
#
# Version history:
#
# 1.1:
#
#      - Loading the required assembly System.Web now. This was missing earlier.
#
# 1.0: Initial version
#

[CmdletBinding()]
param($path)

# Load required assemblies
[void] [System.Reflection.Assembly]::Load("System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")

$tokenColours = @{
    'Attribute' = '#FFADD8E6'
    'Command' = '#FF0000FF'
    'CommandArgument' = '#FF8A2BE2'
    'CommandParameter' = '#FF000080'
    'Comment' = '#FF006400'
    'GroupEnd' = '#FF000000'
    'GroupStart' = '#FF000000'
    'Keyword' = '#FF00008B'
    'LineContinuation' = '#FF000000'
    'LoopLabel' = '#FF00008B'
    'Member' = '#FF000000'
    'NewLine' = '#FF000000'
    'Number' = '#FF800080'
    'Operator' = '#FFA9A9A9'
    'Position' = '#FF000000'
    'StatementSeparator' = '#FF000000'
    'String' = '#FF8B0000'
    'Type' = '#FF008080'
    'Unknown' = '#FF000000'
    'Variable' = '#FFFF4500'
}

# Generate an HTML span and append it to HTML string builder
$currentLine = 1
function Append-HtmlSpan ($block, $tokenColor)
{
   if (($tokenColor -eq 'NewLine') -or ($tokenColor -eq 'LineContinuation'))
   {
      if($tokenColor -eq 'LineContinuation')
      {
         $null = $codeBuilder.Append('`')
      }

      $null = $codeBuilder.Append("<br />`r`n")
   }
   else
   {
      $block = [System.Web.HttpUtility]::HtmlEncode($block)
      if (-not $block.Trim())
      {
         $block = $block.Replace(' ', '&nbsp;')
      }

      $htmlColor = $tokenColours[$tokenColor].ToString().Replace('#FF', '#')

      if($tokenColor -eq 'String')
      {
         $lines = $block -split "`r`n"
         $block = ""

         $multipleLines = $false
         foreach($line in $lines)
         {
            if($multipleLines)
            {
               $block += "<BR />`r`n"
            }

            $newText = $line.TrimStart()
            $newText = "&nbsp;" * ($line.Length - $newText.Length) + $newText
            $block += $newText
            $multipleLines = $true
         }
      }

      $null = $codeBuilder.Append("<span style='color:$htmlColor'>$block</span>")
   }
}

function Main
{
   $text = $null

   if($path)
   {
      $text = (Get-Content $path) -join "`r`n"
   }
   else
   {
      Write-Error 'Please supply the path to the PowerShell script to syntax highlight as first (and only) parameter.'
      return
   }

   trap { break }

   # Do syntax parsing.
   $errors = $null
   $tokens = [system.management.automation.psparser]::Tokenize($Text, [ref] $errors)

   # Initialize HTML builder.
   $codeBuilder = new-object system.text.stringbuilder

   # Iterate over the tokens and set the colors appropriately.
   $position = 0
   foreach ($token in $tokens)
   {
      if ($position -lt $token.Start)
      {
         $block = $text.Substring($position, ($token.Start - $position))
         $tokenColor = 'Unknown'
         Append-HtmlSpan $block $tokenColor
      }

      $block = $text.Substring($token.Start, $token.Length)
      $tokenColor = $token.Type.ToString()
      Append-HtmlSpan $block $tokenColor

      $position = $token.Start + $token.Length
   }

   # Build the entire syntax-highlighted script
   $code = $codeBuilder.ToString()
   
   # Replace tabs with three blanks
   $code   = $code -replace "\t","   "

   # Write the HTML to a file
   $code | set-content -path "$path.html"
}

. Main