The sub is good except that it does not work properly for all characters, I suggest the flw lines instead.

If any body find a mistake in flw code, pls mail to mouradselim@yahoo.com ,I am just a beginner. Thanks.

$data="this is a test&for=many[of]non_alpha)numeric(charracters*";
$_=$data;

    foreach (split //,$_){
        if ($_ eq " ") { $out.="+"; next; }    
        if((ord($_) >= 0x41 && ord($_) <= 0x5a) ||
           (ord($_) >= 0x61 && ord($_) <= 0x7a) || 
           (ord($_) >= 0x30 && ord($_) <= 0x39))
        {
            $out.=$_ ;
        }
        else {
            $out.=sprintf("%%%02X",ord($_)); 
        }
    }
print "$out";
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Edit kudra, 2002-02-23 Added code tags