Sucuri JAVASCRIPT

<html>
<head>
<title>Criptografia</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
</head>
<body>
<script language="javascript">
function Encripta(dados){
	var mensx="";
	var l;
	var i;
	var j=0;
	var ch;
	ch = "ToHaCkIaNdOtOdOmUnDo!";
	for (i=0;i<dados.length; i++){
		j++;
		l=(Asc(dados.substr(i,1))+(Asc(ch.substr(j,1))));
		if (j==50){
			j=1;
		}
		if (l>255){
			l-=256;
		}
		mensx+=(Chr(l));
	}
	document.getElementById("1").value=mensx;
}
function Descripta(dados){
	var mensx="";
	var l;
	var i;
	var j=0;
	var ch;
	ch = "ToHaCkIaNdOtOdOmUnDo!";
	for (i=0; i<dados.length;i++){
		j++;
		l=(Asc(dados.substr(i,1))-(Asc(ch.substr(j,1))));
		if (j==50){
			j=1;
		}
		if (l<0){
			l+=256;
		}
		mensx+=(Chr(l));
	}
	document.getElementById("2").value=mensx;
}
function Asc(String){
	return String.charCodeAt(0);
}

function Chr(AsciiNum){
	return String.fromCharCode(AsciiNum)
}
</script>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
  <tr>
    <td align="center">Dado a ser criptografado </td>
    <td align="center">Criptografia</td>
    <td align="center">Descriptografia</td>
  </tr>
  <tr>
    <td align="center"><textarea name="1" id="0" rows="5" onKeyPress="return enter(event, this);"></textarea></td>
    <td align="center"><textarea name="2" id="1" rows="5" onKeyPress="return enter(event, this);"></textarea></td>
    <td align="center"><textarea name="3" id="2" rows="5" onKeyPress="return enter(event, this);"></textarea></td>
  </tr>
</table>
<div align="center"><br />
  <br />
  <input type="button" value="Limpar Campos" onClick="limpar();"/>
    <script language="javascript">
document.getElementById("0").focus();
function enter(event, envia){
	var keyCode = event.keyCode ? event.keyCode : event.which ? event.which : event.charCode;
	if (keyCode == 13){
		var dados=document.getElementById(envia.id);
		var next=(parseInt(envia.id)+1);
		if(dados.value.lenght<=0){
			return false;
		}else{
			if (envia.id==0){
				Encripta(dados.value);
				document.getElementById(next).focus();
			}else if(envia.id==1){
				Descripta(dados.value);
				document.getElementById(next).focus();
			}else{
				limpar();
			}
			return false;
		}
	}else{
		return true;
	}
}
function limpar(){
	for (var i=0; i<3;i++){
		document.getElementById(i).value="";
	}
	document.getElementById(0).focus();
}
  </script>
</div>
</body>
</html>