Cryptography in JS Help?

// This function is pretty simple
function frequencyanalysis(text){
text = text.split(" ").join("").toUpperCase();
var textL = text.length;
var hashtable = new Array(0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0);
var alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
// Nested loop to find frequencies and input them into the hashtable

for (d=0; d<=25; d++) {
    for (i=0; i<=textL; i++){
         if (text.charAt(i) === alphabet.charAt(d)){
         hashtable[d] = hashtable[d] + 1;
        }
    }
}
return hashtable;
}


// This function makes Index of Coincidence Happen | 1.0 = Random Text/Polyalphabetic Cipher 1.73 = Standard English/Monoalphabetic Cipher
function indexofcoincidence(text){
text = text.split(" ").join("").toUpperCase();
var textL = text.length;
var hashtable = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0];
var alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
for (d=0; d<=25; d++) {
    for (i=0; i < textL; i++){
        if (text.charAt(i) === alphabet.charAt(d)){
        hashtable[d] = hashtable[d] + 1;
        }
    }
}

var aa = hashtable[0]/textL;
var A = aa*aa;
var bb = hashtable[1]/textL;
var B = bb*bb;
var cc = hashtable[2]/textL;
var C = cc*cc;
var dd = hashtable[3]/textL;
var D = dd*dd;
var ee = hashtable[4]/textL;
var E = ee*ee;
var ff = hashtable[5]/textL;
var F = ff*ff;
var gg = hashtable[6]/textL;
var G = gg*gg;
var hh = hashtable[7]/textL;
var H = hh*hh;
var ii = hashtable[8]/textL;
var I = ii*ii;
var jj = hashtable[9]/textL;
var J = jj*jj;
var kk = hashtable[10]/textL;
var K = kk*kk;
var ll = hashtable[11]/textL;
var L = ll*ll;
var mm = hashtable[12]/textL;
var M = mm*mm;
var nn = hashtable[13]/textL;

var N = nn*nn;
var oo = hashtable[14]/textL;
var O = oo*oo;
var pp = hashtable[15]/textL;
var P = pp*pp;
var qq = hashtable[16]/textL;
var Q = qq*qq;
var rr = hashtable[17]/textL;
var R = rr*rr;
var ss = hashtable[18]/textL;
var S = ss*ss;
var tt = hashtable[19]/textL;
var T = tt*tt;
var uu = hashtable[20]/textL;
var U = uu*uu;
var vv = hashtable[21]/textL;
var V = vv*vv;
var ww = hashtable[22]/textL;
var W = ww*ww;
var xx = hashtable[23]/textL;
var X = xx*xx;
var yy = hashtable[24]/textL;
var Y = yy*yy;
var zz = hashtable[25]/textL;
var Z = zz*zz;

var Kappa = A+B+C+D+E+F+G+H+I+J+K+L+M+N+O+P+Q+R+S+T+U+V+W+X+Y+Z;

var Top = 0.027*textL;
var Bottom1 = 0.038*textL + 0.065;
var Bottom2 = (textL - 1)*Kappa;
var KeyLength = Top/(Bottom2 - Bottom1) ;

return Kappa/0.0385;
}

function keylengthfinder(text){
    // Average Function Definition
    Array.prototype.avg = function() {
var av = 0;
var cnt = 0;
var len = this.length;
for (var i = 0; i < len; i++) {
var e = +this[i];
if(!e && this[i] !== 0 && this[i] !== '0') e--;
if (this[i] == e) {av += e; cnt++;}
}
return av/cnt;
}
    // Begin the Key Length Finding
    var textL = text.length;
    var hashtable = new Array(0,0,0,0,0,0,0,0,0,0,0,0);
        for (a = 0; a <= 12; a++){ // This is the main loop, testing each key length
            var stringtable = [];
            for (z = 0; z <= a; z++){ // This allows each setting, ie. 1st, 4th, 7th AND 2nd, 5th, 8th to be tested
                for (i = z; i < textL; i + a){
                    var string = '';
                    string = string.concat(text.charAt(i)); // Join each letter of the correct place in the string
                    stringtable[z] = indexofcoincidence(string);
                    }
                }
            hashtable[a] = stringtable.avg();
        }
    return hashtable;
}