<!--
//cd18.js
function stopErrors() {
 return true;
}
window.onerror = stopErrors;

function selectAll(theField) {
var tempval=eval("document."+theField)
tempval.focus()
tempval.select()
}

defaultStatus = "Level 5"  

/*
Slide Encryption Program
This program works by searching for each character in
the char_set variable and sliding that character based
on the number in the pull down select.
*/


var char_set = '$%^NOZ1&PQR(./~`"CDEFG!@STUVWZghij}:<pHB*#8uvwx>?[]\',ef34590qrklmnoIJ)_+{st67 abcdAyzKLM2Y';

function encrypt_data() {
var input = window.input.input_field.value;
var output = "";
var char_code;

//get algorithm from pull down select
var algorithm = window.input.shift_select.selectedIndex;
algorithm++;

var alpha_length = char_set.length - algorithm;
var space;

//begin for loop to cycle through input
for (loop=0; loop<input.length; loop++) {

//if conditional detects unknown characters
if (char_set.indexOf(input.charAt(loop)) == -1) {
alert("Program Error: Unknown Character!");
}

//search char_set string for character and set char_code variable...
char_code = char_set.indexOf(input.charAt(loop));

//actual text encoding algorithm goes here
if (char_code + algorithm > char_set.length)
{
space = char_set.length - char_code;
char_code = algorithm - space;
}
else
{
char_code += algorithm;
}

//set output variable in accordance to char_set
output += char_set.charAt(char_code);
}
//dump contents of output variable into textarea
window.input.input_field.value = output;
}


function decrypt_data() {
var input = window.input.input_field.value;
var output = "";
var char_code;

//get algorithm from pull down select
var algorithm = window.input.shift_select.selectedIndex;
algorithm++;

var alpha_length = char_set.length - algorithm;
var space;

//begin for loop to cycle through input
for (loop=0; loop<input.length; loop++) {

//if conditional detects unknown characters
if (char_set.indexOf(input.charAt(loop)) == -1) {
alert("Program Error: Unknown Character!");
}

//search char_set string for character and set char_code variable...
char_code = char_set.indexOf(input.charAt(loop));

//oppisite of encrypt algorithm goes here
if (char_code - algorithm < 0)
{
space = algorithm - char_code;
char_code = char_set.length - space;
}
else
{
char_code -= algorithm;
}

//set output variable in accordance to char_set
output += char_set.charAt(char_code);
}
//dump contents of output variable into textarea
window.input.input_field.value = output;
}
//-->