Obfuscating email addresses in HTML

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Views: 516 | Replies: 2

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Join Date: Aug 2007

Posts: 52

Reputation: Fest3er is an unknown quantity at this point

Rep Power: 2

Solved Threads: 2

Fest3er

Offline

Junior Poster in Training

Obfuscating email addresses in HTML

Jan 2nd, 2008

I've created a fairly simple method for obfuscating email addresses as an anti-spam measure. It should work for any browser that supports JavaScript and a fairly modern Document Object Model (DOM). A composer window in the user's default email application will be opened.

First up is the javascript function that assembles the mailto: url and 'submits' it:

 Help with Code Tags 
 javascript Syntax (Toggle Plain Text) 
<script language="javascript">
  // Action taken when an email 'link' is clicked
  function local_emclick(parm1, parm2)
  {
    test_4 = "lto:";
    d37 = "@";
    t2 = "mai";
    parm = t2+test_4+parm1+d37+parm2;
    self.location = parm;
  }
</script>
<script language="javascript">
  // Action taken when an email 'link' is clicked
  function local_emclick(parm1, parm2)
  {
    test_4 = "lto:";
    d37 = "@";
    t2 = "mai";
    parm = t2+test_4+parm1+d37+parm2;
    self.location = parm;
  }
</script>

You should customize everything (but the script tags and function and self.location) to prevent spammers from learning to recognize the pattern. Even the order of the parameters should be customized.

Next up is the PHP function that eases using this method:

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
  function local_emlink($one, $two, $three, $four, $five="")
  {
    if ($five!="")
    {
      $smso = "<b>"; $rmso = "</b>";
    }
    else
    {
      $smso = ""; $rmso = "";
    }
    print("$smso<a class=\"$two\" href=\"about:\" onclick='local_emclick(\"$one\", \"$three\"); return false;'>$four</a>$rmso");
  }
  function local_emlink($one, $two, $three, $four, $five="")
  {
    if ($five!="")
    {
      $smso = "<b>"; $rmso = "</b>";
    }
    else
    {
      $smso = ""; $rmso = "";
    }
    print("$smso<a class=\"$two\" href=\"about<b></b>:\" onclick='local_emclick(\"$one\", \"$three\"); return false;'>$four</a>$rmso");
  }

An example of its use is:

 Help with Code Tags 
 html Syntax (Toggle Plain Text) 
<p style="text-align:center; margin:2pt 18pt; text-indent:0;
         background-color: #CC9966; font-size:7.5pt; font-weight:bold;
         text-decoration:underline">
  Sample Company<br>
  012 Rhode St.<br>
  Notown, MI 00000<br>
  (123)555-7890<br>
  Fax: (123)555-7891<br>
  <?php local_emlink("info", "header", "sample.com", "Contact"); ?>
</p>
<p style="text-align:center; margin:2pt 18pt; text-indent:0;
         background-color: #CC9966; font-size:7.5pt; font-weight:bold;
         text-decoration:underline">
  Sample Company<br>
  012 Rhode St.<br>
  Notown, MI 00000<br>
  (123)555-7890<br>
  Fax: (123)555-7891<br>
  <?php local_emlink("info", "header", "sample.com", "Contact"); ?>
</p>

If you don't have access to PHP, then you can create the link directly in HTML. This is the same HTML generated by the PHP, except for whitespace::

 Help with Code Tags 
 html Syntax (Toggle Plain Text) 
<a class="header"
   href="about:"
   onclick='local_emclick("info", "sample.com");
            return false;'>Contact</a>
<a class="header"
   href="about<b></b>:"
   onclick='local_emclick("info", "sample.com");
            return false;'>Contact</a>

Last edited by Fest3er : Jan 2nd, 2008 at 3:57 pm.

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Join Date: Dec 2007

Location: www.JavaScriptBank.com

Posts: 5

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temp304

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Newbie Poster

Re: Obfuscating email addresses in HTML

Jan 3rd, 2008

good post, but you should provide demo for these

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Join Date: Aug 2007

Posts: 52

Reputation: Fest3er is an unknown quantity at this point

Rep Power: 2

Solved Threads: 2

Fest3er

Offline

Junior Poster in Training

Re: Obfuscating email addresses in HTML

Jan 3rd, 2008

•

Originally Posted by temp304

good post, but you should provide demo for these

Quite right. Do note that if you copy/paste the examples below, you may receive an error. Daniweb's VB seems to insert "<b></b>" between 'about' and ':' in the HTML example.

Minimal PHP example:

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
<html><body>
 
<?php
 
  function local_emlink($one, $two, $three, $four, $five="")
  {
    if ($five!="")
    {
      $smso = "<b>"; $rmso = "</b>";
    }
    else
    {
      $smso = ""; $rmso = "";
    }
    print("$smso<a class=\"$two\" href=\"about:\" onclick='local_emclick(\"$one\", \"$three\"); return false;'>$four</a>$rmso");
  }
?>
 
<script language="javascript">
  // Action taken when an email 'link' is clicked
  function local_emclick(parm1, parm2)
  {
    test_4 = "lto:";
    d37 = "@";
    t2 = "mai";
    parm = t2+test_4+parm1+d37+parm2;
    self.location = parm;
  }
</script>
 
<p style="text-align:center; margin:2pt 18pt; text-indent:0;
         background-color: #CC9966; font-size:12pt; font-weight:bold;
         text-decoration:underline">
  Example Company<br>
  012 Rhode St.<br>
  Notown, MI 00000<br>
  (123)555-7890<br>
  Fax: (123)555-7891<br>
  <?php local_emlink("info", "header", "example.com", "Contact"); ?>
</p>
 
</body></html>
<html><body>

<?php

  function local_emlink($one, $two, $three, $four, $five="")
  {
    if ($five!="")
    {
      $smso = "<b>"; $rmso = "</b>";
    }
    else
    {
      $smso = ""; $rmso = "";
    }
    print("$smso<a class=\"$two\" href=\"about<b></b>:\" onclick='local_emclick(\"$one\", \"$three\"); return false;'>$four</a>$rmso");
  }
?>

<script language="javascript">
  // Action taken when an email 'link' is clicked
  function local_emclick(parm1, parm2)
  {
    test_4 = "lto:";
    d37 = "@";
    t2 = "mai";
    parm = t2+test_4+parm1+d37+parm2;
    self.location = parm;
  }
</script>

<p style="text-align:center; margin:2pt 18pt; text-indent:0;
         background-color: #CC9966; font-size:12pt; font-weight:bold;
         text-decoration:underline">
  Example Company<br>
  012 Rhode St.<br>
  Notown, MI 00000<br>
  (123)555-7890<br>
  Fax: (123)555-7891<br>
  <?php local_emlink("info", "header", "example.com", "Contact"); ?>
</p>

</body></html>

Minimal HTML example (produce by the above PHP):

 Help with Code Tags 
 html Syntax (Toggle Plain Text) 
<html><body>
 
 
<script language="javascript">
  // Action taken when an email 'link' is clicked
  function local_emclick(parm1, parm2)
  {
    test_4 = "lto:";
    d37 = "@";
    t2 = "mai";
    parm = t2+test_4+parm1+d37+parm2;
    self.location = parm;
  }
</script>
 
<p style="text-align:center; margin:2pt 18pt; text-indent:0;
         background-color: #CC9966; font-size:12pt; font-weight:bold;
         text-decoration:underline">
  Example Company<br>
  012 Rhode St.<br>
  Notown, MI 00000<br>
  (123)555-7890<br>
  Fax: (123)555-7891<br>
  <a class="header" href="about:" onclick='local_emclick("info", "example.com"); return false;'>Contact</a></p>
 
</body></html>
<html><body>


<script language="javascript">
  // Action taken when an email 'link' is clicked
  function local_emclick(parm1, parm2)
  {
    test_4 = "lto:";
    d37 = "@";
    t2 = "mai";
    parm = t2+test_4+parm1+d37+parm2;
    self.location = parm;
  }
</script>

<p style="text-align:center; margin:2pt 18pt; text-indent:0;
         background-color: #CC9966; font-size:12pt; font-weight:bold;
         text-decoration:underline">
  Example Company<br>
  012 Rhode St.<br>
  Notown, MI 00000<br>
  (123)555-7890<br>
  Fax: (123)555-7891<br>
  <a class="header" href="about<b></b>:" onclick='local_emclick("info", "example.com"); return false;'>Contact</a></p>

</body></html>