Simple HTML Scrambler

• 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.

<%@ 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.