var elem = document.getElementById("e-m");

elem.innerHTML = decryptText("jogpAkpoept/ef");

    function decryptText( s )
    {
        var n = 0;
        var r = "";
        for( var i = 0; i < s.length; i++)
        {
            n = s.charCodeAt( i );
            if( n >= 8364 )
            {
                n = 128;
            }
            r += String.fromCharCode( n - 1 );
        }
        return r;
    }


/*
    function encryptText(s)
    {
        var n = 0;
        var r = "";

        for( var i=0; i < s.length; i++ )
        {
            n = s.charCodeAt( i );
            if( n >= 8364 )
            {
                n = 128;
            }
            r += String.fromCharCode(n+1);
        }
        return r;
    }
*/