Simple HTML Scrambler

StianSandberg

Rate me:

4.60/5 (4 votes)

19 Dec 2007CPOL

47.2K

318

A server control for scrambling HTML code/

Download source code - 2.35 KB

Introduction

This server-control was developed for hiding mail-links. If you put your email-address in a mailto-link, you will receive spam-mail, but you can use simple JavaScript to avoid this. This server-control can wrap your HTML and scramble it with simple JavaScript. The control inherits from a Literal control which is used for plain-text rendering.

Using the code

HTMLScrambler is easy to use. Just put the control around your HTML, and it's ready to go.

ASP.NET

<%@ Register Assembly="Serverside.HTMLScrambler" 
    Namespace="Serverside.HTMLScrambler" TagPrefix="uc1" %>

......

<uc1:HTMLScrambler runat="server" id="HTMLScrambler1" Mode="HTML">
  this text/html will be scrambled with HTML.
</uc1:HTMLScrambler>

<hr />

<uc1:HTMLScrambler runat="server" id="HTMLScrambler2" Mode="Javascript">
  this text/html will be scrambled with Javascript.
</uc1:HTMLScrambler>

The control supports two ways to scramble: JavaScript or HTML. It's basically four small functions to get this working.

// Used for javascript scramble
private string GetHex(string character)
{
    String[] hex = { "00", "01", "02", "03", "04", "05", "06", "07", "08", "09", 
         "0A", "0B", "0C", "0D", "0E", "0F", "10", "11", "12", "13", 
         "14", "15", "16", "17", "18", "19", "1A", "1B", "1C", "1D", 
         "1E", "1F", "20", "21", "22", "23", "24", "25", "26", "27", 
         "28", "29", "2A", "2B", "2C", "2D", "2E", "2F", "30", "31", 
         "32", "33", "34", "35", "36", "37", "38", "39", "3A", "3B", 
         "3C", "3D", "3E", "3F", "40", "41", "42", "43", "44", "45", 
         "46", "47", "48", "49", "4A", "4B", "4C", "4D", "4E", "4F", 
         "50", "51", "52", "53", "54", "55", "56", "57", "58", "59", 
         "5A", "5B", "5C", "5D", "5E", "5F", "60", "61", "62", "63", 
         "64", "65", "66", "67", "68", "69", "6A", "6B", "6C", "6D", 
         "6E", "6F", "70", "71", "72", "73", "74", "75", "76", "77", 
         "78", "79", "7A", "7B", "7C", "7D", "7E", "7F", "80", "81", 
         "82", "83", "84", "85", "86", "87", "88", "89", "8A", "8B", 
         "8C", "8D", "8E", "8F", "90", "91", "92", "93", "94", "95", 
         "96", "97", "98", "99", "9A", "9B", "9C", "9D", "9E", "9F", 
         "A0", "A1", "A2", "A3", "A4", "A5", "A6", "A7", "A8", "A9", 
         "AA", "AB", "AC", "AD", "AE", "AF", "B0", "B1", "B2", "B3", 
         "B4", "B5", "B6", "B7", "B8", "B9", "BA", "BB", "BC", "BD", 
         "BE", "BF", "C0", "C1", "C2", "C3", "C4", "C5", "C6", "C7", 
         "C8", "C9", "CA", "CB", "CC", "CD", "CE", "CF", "D0", "D1", 
         "D2", "D3", "D4", "D5", "D6", "D7", "D8", "D9", "DA", "DB", 
         "DC", "DD", "DE", "DF", "E0", "E1", "E2", "E3", "E4", "E5", 
         "E6", "E7", "E8", "E9", "EA", "EB", "EC", "ED", "EE", "EF", 
         "F0", "F1", "F2", "F3", "F4", "F5", "F6", "F7", "F8", "F9", 
         "FA", "FB", "FC", "FD", "FE", "FF" };
    char[] chrBuffer = { Convert.ToChar(character) };
    byte[] bytBuffer = Encoding.Default.GetBytes(chrBuffer);
    int chrIndex = (int)bytBuffer[0];
    return hex[chrIndex];
}


// Used for html-scramble
private string GetCharcode(string character)
{
    char[] chrBuffer = { Convert.ToChar(character) };
    byte[] bytBuffer = Encoding.Default.GetBytes(chrBuffer);
    int chrIndex = (int)bytBuffer[0];
    return "&#" + chrIndex + ";";
}

The scramble-function:

private string Scramble(string HTML)
{
    try
    {
        StringBuilder js = new StringBuilder();
        if (Mode == ScrambleMode.Javascript)
        {
            js.Append("<script type=\"text/javascript\">");
            js.Append("var i,y,x=");
            js.Append("\"");
            for (int i = 0; i < HTML.Length; i++)
            {
                js.Append(this.GetHex(HTML.Substring(i, 1)));
            }
            js.Append("\";");
            js.Append("y='';");
            js.Append("for(i=0;i<x.length;i+=2)");
            js.Append("{");
            js.Append("y+=unescape('%'+x.substr(i,2));");
            js.Append("}");
            js.Append("document.write(y);");
            js.Append("</script>");
        }
        else if (Mode == ScrambleMode.HTML)
        {
            for (int i = 0; i < HTML.Length; i++)
            {
                js.Append(this.GetCharcode(HTML.Substring(i, 1)));
            }
        }
        return js.ToString();
    }
    catch
    {
        return HTML;
    }
}

The control needs a Render method which scrambles all the text in the control.

protected override void Render(HtmlTextWriter writer)
{
    writer.Write(Scramble(this.Text.Trim()));
}

Enums and a rpoperty for making it easier to use in code

private ScrambleMode _mode = ScrambleMode.Javascript;
// Default is javascript

public new ScrambleMode Mode
{
    get { return _mode; }
    set { _mode = value; }
}

public enum ScrambleMode
{
    HTML = 1,
    Javascript = 2
}

And, that's it.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By

StianSandberg

Software Developer (Senior) Aurum AS

Norway

Microsoft Certified Solutions Developer (MCSD)

Personal website:
stian.net

My projects:
CRM1.no - A free to use norwegian crm software
Fakturax - A free to use norwegian invoice software
Timeføring.no - A free to use norwegian timereg software
MittUtlegg - A free to use norwegian software for receipts
SupportWeb - A free to use norwegian software customersupport

public sealed class HTMLScrambler : System.Web.UI.WebControls.Literal { private static readonly string[] HEX = { "00", "01", "02", "03", "04", "05", "06", "07", "08", "09", "0A", "0B", "0C", "0D", "0E", "0F", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "1A", "1B", "1C", "1D", "1E", "1F", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "2A", "2B", "2C", "2D", "2E", "2F", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "3A", "3B", "3C", "3D", "3E", "3F", "40", "41", "42", "43", "44", "45", "46", "47", "48", "49", "4A", "4B", "4C", "4D", "4E", "4F", "50", "51", "52", "53", "54", "55", "56", "57", "58", "59", "5A", "5B", "5C", "5D", "5E", "5F", "60", "61", "62", "63", "64", "65", "66", "67", "68", "69", "6A", "6B", "6C", "6D", "6E", "6F", "70", "71", "72", "73", "74", "75", "76", "77", "78", "79", "7A", "7B", "7C", "7D", "7E", "7F", "80", "81", "82", "83", "84", "85", "86", "87", "88", "89", "8A", "8B", "8C", "8D", "8E", "8F", "90", "91", "92", "93", "94", "95", "96", "97", "98", "99", "9A", "9B", "9C", "9D", "9E", "9F", "A0", "A1", "A2", "A3", "A4", "A5", "A6", "A7", "A8", "A9", "AA", "AB", "AC", "AD", "AE", "AF", "B0", "B1", "B2", "B3", "B4", "B5", "B6", "B7", "B8", "B9", "BA", "BB", "BC", "BD", "BE", "BF", "C0", "C1", "C2", "C3", "C4", "C5", "C6", "C7", "C8", "C9", "CA", "CB", "CC", "CD", "CE", "CF", "D0", "D1", "D2", "D3", "D4", "D5", "D6", "D7", "D8", "D9", "DA", "DB", "DC", "DD", "DE", "DF", "E0", "E1", "E2", "E3", "E4", "E5", "E6", "E7", "E8", "E9", "EA", "EB", "EC", "ED", "EE", "EF", "F0", "F1", "F2", "F3", "F4", "F5", "F6", "F7", "F8", "F9", "FA", "FB", "FC", "FD", "FE", "FF" }; private string _output = null; public enum ScrambleMode { HTML = 1, Javascript = 2 } private ScrambleMode _mode = ScrambleMode.Javascript; public new ScrambleMode Mode { get { return _mode; } set { _mode = value; } } protected override void OnPreRender(EventArgs e) { base.OnPreRender(e); _output = Scramble(this.Text.Trim()); } protected override void Render(HtmlTextWriter writer) { writer.Write(_output); } private string Scramble(string HTML) { try { StringBuilder js = new StringBuilder(HTML.Length*5); if (Mode == ScrambleMode.Javascript) { const string JS_Scramble = "JS_Scramble"; if (!this.Page.ClientScript.IsClientScriptBlockRegistered(this.Page.GetType(), JS_Scramble)) { const string JS_ScrambleScript = "<script type=\"text/javascript\">"+ "function JSScramble(data){"+ "var i,y;"+ "y='';"+ "for(i=0;i<data.length;i+=2)"+ "y+=unescape('%'+data.substr(i,2));"+ "return y;}"+ "</script>"; this.Page.ClientScript.RegisterClientScriptBlock(this.Page.GetType(), JS_Scramble, JS_ScrambleScript); } js.Append("<script type=\"text/javascript\">"); js.Append("document.write(JSScramble('"); for (int i = 0, len = HTML.Length; i != len; ++i) { js.Append(GetHex(HTML[i])); } js.Append("'));"); js.Append("</script>"); } else /*if (Mode == ScrambleMode.HTML)*/ //implied { for (int i = 0, len=HTML.Length; i!=len; ++i) { js.Append(GetCharcode(HTML[i])); } } return js.ToString(); } catch { return HTML; } } private static string GetHex(char character) { char[] chrBuffer = { character }; byte[] bytBuffer = Encoding.Default.GetBytes(chrBuffer); return HEX[(int)bytBuffer[0]]; } private static string GetCharcode(char character) { char[] chrBuffer = { character }; byte[] bytBuffer = Encoding.Default.GetBytes(chrBuffer); return "&#" + (int)bytBuffer[0] + ";"; } }

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

Simple HTML Scrambler

Introduction

Using the code

License

Comments and Discussions