4. The code
The "hide_email()" PHP function is only 9 lines of code:
function hide_email($email)
{ $character_set = '+-.0123456789@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz';
$key = str_shuffle($character_set); $cipher_text = ''; $id = 'e'.rand(1,999999999);
for ($i=0;$i<strlen($email);$i+=1) $cipher_text.= $key[strpos($character_set,$email[$i])];
$script = 'var a="'.$key.'";var b=a.split("").sort().join("");var c="'.$cipher_text.'";var d="";';
$script.= 'for(var e=0;e<c.length;e++)d+=b.charAt(a.indexOf(c.charAt(e)));';
$script.= 'document.getElementById("'.$id.'").innerHTML="<a href=\\"mailto:"+d+"\\">"+d+"</a>"';
$script = "eval(\"".str_replace(array("\\",'"'),array("\\\\",'\"'), $script)."\")";
$script = '<script type="text/javascript">/*<![CDATA[*/'.$script.'/*]]>*/</script>';
return '<span id="'.$id.'">[javascript protected email address]</span>'.$script;
}