// @nuget: HtmlAgilityPack

​

using System;

using System.Xml;

using System.Linq;

using HtmlAgilityPack;

public class Program

{

    public static void Main()

    {

        var html = 

        @"<TD class=texte width=""50%"">

            <DIV align=right>Name :<B> </B></DIV>

        </TD>

        <TD width=""50%"">

            <INPUT class=box value=John maxLength=16 size=16 name=user_name>

            <INPUT class=box value=Tony maxLength=16 size=16 name=user_name>

            <INPUT class=box value=Jams maxLength=16 size=16 name=user_name>

        </TD>

        <TR vAlign=center>";

​

        var htmlDoc = new HtmlDocument();

        htmlDoc.LoadHtml(html);

​

        string name = htmlDoc.DocumentNode

                        .SelectNodes("//td/input")

                        .First()

                        .Attributes["value"].Value;

        Console.WriteLine(name);

    }

}