Does Html Agility Pack support HTML5 tags?

Yes, the Html Agility Pack (HAP) does support HTML5 tags. Html Agility Pack is a flexible and versatile library that allows you to parse and manipulate HTML documents in .NET environments. It is often used for web scraping, as it can handle poorly formed HTML that might not be valid XHTML.

HTML5 introduced a number of new elements and attributes that are designed to help organize and structure content on the web more semantically. Since HAP is designed to be a tolerant parsing system, it can handle various HTML doctypes, including HTML5. The parser will not reject HTML5 tags; it will treat them as it would any other tags.

However, it's important to note that Html Agility Pack doesn't inherently know what HTML5 tags are supposed to do from a browser rendering perspective. It only knows how to parse them as part of the document's node structure. This means that while HAP supports HTML5 tags in the sense that it can recognize and parse them, any functionality specific to HTML5 (like the behavior of the <canvas> element or the form validation attributes) is outside the scope of what HAP deals with.

Here's a basic example of how you might use Html Agility Pack to parse an HTML5 document in C#:

using HtmlAgilityPack;
using System;
using System.Net.Http;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        var url = "http://example.com"; // Replace with your target URL
        var httpClient = new HttpClient();
        var html = await httpClient.GetStringAsync(url);

        var htmlDoc = new HtmlDocument();
        htmlDoc.LoadHtml(html);

        // Example: Select HTML5 elements like <article>
        var articles = htmlDoc.DocumentNode.SelectNodes("//article");

        if (articles != null)
        {
            foreach (var article in articles)
            {
                Console.WriteLine(article.InnerHtml);
            }
        }
        else
        {
            Console.WriteLine("No <article> tags found.");
        }
    }
}

In this example, we use an HttpClient to get HTML content from a URL, load it into an HtmlDocument object, and then use XPath to select all <article> elements, which is an HTML5 tag. The SelectNodes method is used to query the document for nodes that match the XPath expression.

Remember to install Html Agility Pack via NuGet before running this code:

Install-Package HtmlAgilityPack

Since you're dealing with HTML5, you might also encounter scenarios where you need to handle specific character sets, new input types, or multimedia elements. While HAP will parse these elements, any specialized processing or handling for HTML5-specific features will need to be implemented separately by the developer.