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function that randomly sorts through letters and changes them not working

I am making a javascript function that will input a string, and output a "spongebob mocking text"
basically, you input "Hello, this is a message to the world" and you would get "HeLlO, ThIS iS a MeSsAGe tO tHE wORlD"
basically, randomly decide wheather to capitalize a letter or not. I made a function which i thought would do that, but it didn't work. here is the code that I tested in the js console:
function memify(input) { // function called memify()
var il = input.length; // gets the length of the input
var newinput = input; // creates a new variable that will be changed from input.
for (var i=0;i>il;i++) {
var rng = Math.floor((Math.random()*2)); // random number between 0 and 1. 0 = upper 1 = lower
if (rng === 0) {
newinput.charAt(i).toUpperCase();
}
else {
newinput.charAt(i).toLowerCase();
}
}
return newinput;
}
var text = prompt();
var textmeme = memify(text);
alert(textmeme);
Why is this not working? Do I have an error in my code? Any help will be greatly appreciated.

When you do
newinput.charAt(i).toUpperCase();
you're creating a new uppercase character, but you aren't doing anything with it; it's just an unused expression, so there's no visible change. Primitives (including strings) are immutable - you should explicitly reassign a string to something else (eg newString += newinput.charAt(i).toUpperCase();) to see an effect.
You also need to use
for (var i = 0; i < il; i++) {
// ^
instead of
for (var i = 0; i > il; i++) {
// ^
else, no iterations will run at all.
function memify(input) { // function called memify()
var il = input.length; // gets the length of the input
let changedStr = '';
for (var i = 0; i < il; i++) {
var rng = Math.floor((Math.random() * 2)); // random number between 0 and 1. 0 = upper 1 = lower
if (rng === 0) {
changedStr += input.charAt(i).toUpperCase();
} else {
changedStr += input.charAt(i).toLowerCase();
}
}
return changedStr;
}
var text = prompt();
var textmeme = memify(text);
console.log(textmeme);
Another option, using .map, which looks much cleaner IMO:
const memify = input => [...input]
.map(char => Math.random() < 0.5 ? char.toUpperCase() : char.toLowerCase())
.join('');
console.log(memify(prompt()));

Or more concise, safer and generally better solution :). It does not require for loop, checking length of string and other error prone stuff.
function memify(input) {
var rng = () => Math.random() > 0.5;
var res = input.split('').map( letter =>
rng() ? letter.toUpperCase() : letter.toLowerCase()
).join('');
return res;
}
var textmeme = memify("Hello World");
console.log(textmeme);
Please up-vote if it was helpful :)

Looping through an array that has binary numbers and writing true if the number is 1 or false if the number is 0

I am trying to make a webpage that makes an encrypted letter by first parsing a single character in ascii then parsing the ascii into binary then putting the binary into an array. After putting it into an array I have to loop through the array and write true for "1" or false for "0". Then I have to output to the page. an example of what the output would look like if you put in the letter "a" would be "false,true,true,false,false,false,false,true"
Update: I have added the "loop" in order to make sense of my problem
$(document).ready(function()
{
var output = document.getElementById("output");
var strQuestion = "Enter ONE character, matey!";
var strStandard = "J";
var chrCharacter = "";
var chrLength = 0;
var array = [];
var arrayLength = 0;
while (chrLength != 1)
{
chrCharacter = prompt(strQuestion, strStandard);
chrLength = chrCharacter.length;
}
intAscii = parseAscii(chrCharacter);
strBin = parseBin(intAscii);
array = strBin.split("");
for (i = 0; i < arrayLength; i++ )
{
if (array[i] = 0)
{
array[i] = false;
}
else if (array[i] = 1)
{
array[i] = true;
}
}
output.innerHTML = array;
}); //end document.ready
/*****
Purpose: Converts a character into ascii
Parameters: single character / letter
Return: integer representing an ascii value
*****/
function parseAscii(chrCharacter)
{
intAscii = chrCharacter.charCodeAt(0);
return intAscii;
}
/*****
Purpose: Takes the ascii code and turns it into binary
Parameters: single integer representing an ascii value
Return: binary, base 2 representation of the number passed to this function
*****/
function parseBin(intAscii)
{
strBin = parseInt(intAscii, 10).toString(2);
if(strBin.length < 8)
{
var intPlaceHolders = 8 - strBin.length;
for(var i = 0; i < intPlaceHolders; i++)
{
strBin = "0" + strBin;
}
}
return strBin;
}

I would convert the array with binaries to an array with boolean values wich you can joint together to a string that can be shown on the webpage.
array = [1,1,0,0,1]
// This will map over the items and perform an type conversion
var booleanArray = array.map(Boolean)
// Join all the items together as a string
Var booleanString = booleanArray.join(", ")
output.innerHTML = booleanString
`
I didn't test it, but it should work if I didn't make any typo's.
Btw, I dont think that this is what they ment with looping. But it's definitely a way to get the job done.

If I understand your question correctly, you can convert your array of ones and zeros (binary) to values of ture and false using the map function and using innerHTML to add the output to the DOM:
See example below:
// Populate myBinaryArray using your ascii method to get the follow:
let myBinaryArray = [1, 0, 0, 1, 1, 0, 1];
document.body.innerHTML += myBinaryArray.map(bit => !(!bit));

string occurrences in a string

I'm am working on a script to count the number of times a certain string (in this case, coordinates) occur in a string. I currently have the following:
if (game_data.mode == "incomings") {
var table = document.getElementById("incomings_table");
var rows = table.getElementsByTagName("tr");
var headers = rows[0].getElementsByTagName("th");
var allcoord = new Array(rows.length);
for (i = 1; i < rows.length - 1; i++) {
cells = rows[i].getElementsByTagName("td");
var contents = (cells[1].textContent);
contents = contents.split(/\(/);
contents = contents[contents.length - 1].split(/\)/)[0];
allcoord[i - 1] = contents
}}
So now I have my variable allcoords. If I alert this, it looks like this (depending on the number of coordinates there are on the page):
584|521,590|519,594|513,594|513,590|517,594|513,592|517,590|517,594|513,590|519,,
My goal is that, for each coordinate, it saves how many times that coordinate occurs on the page. I can't seem to figure out how to do so though, so any help would be much appreciated.

you can use regular expression like this
"124682895579215".match(/2/g).length;
It will give you the count of expression
So you can pick say first co-ordinate 584 while iterating then you can use the regular expression to check the count
and just additional information
You can use indexOf to check if string present

I would not handle this as strings. Like, the table, is an array of arrays and those strings you're looking for, are in fact coordinates. Soooo... I made a fiddle, but let's look at the code first.
// Let's have a type for the coordinates
function Coords(x, y) {
this.x = parseInt(x);
this.y = parseInt(y);
return this;
}
// So that we can extend the type as we need
Coords.prototype.CountMatches = function(arr){
// Counts how many times the given Coordinates occur in the given array
var count = 0;
for(var i = 0; i < arr.length; i++){
if (this.x === arr[i].x && this.y === arr[i].y) count++;
}
return count;
};
// Also, since we decided to handle coordinates
// let's have a method to convert a string to Coords.
String.prototype.ToCoords = function () {
var matches = this.match(/[(]{1}(\d+)[|]{1}(\d+)[)]{1}/);
var nums = [];
for (var i = 1; i < matches.length; i++) {
nums.push(matches[i]);
}
return new Coords(nums[0], nums[1]);
};
// Now that we have our types set, let's have an array to store all the coords
var allCoords = [];
// And some fake data for the 'table'
var rows = [
{ td: '04.shovel (633|455) C46' },
{ td: 'Fruits kata misdragingen (590|519)' },
{ td: 'monster magnet (665|506) C56' },
{ td: 'slayer (660|496) C46' },
{ td: 'Fruits kata misdragingen (590|517)' }
];
// Just like you did, we loop through the 'table'
for (var i = 0; i < rows.length; i++) {
var td = rows[i].td; //<-this would be your td text content
// Once we get the string from first td, we use String.prototype.ToCoords
// to convert it to type Coords
allCoords.push(td.ToCoords());
}
// Now we have all the data set up, so let's have one test coordinate
var testCoords = new Coords(660, 496);
// And we use the Coords.prototype.CountMatches on the allCoords array to get the count
var count = testCoords.CountMatches(allCoords);
// count = 1, since slayer is in there

Use the .indexOf() method and count every time it does not return -1, and on each increment pass the previous index value +1 as the new start parameter.

You can use the split method.
string.split('517,594').length-1 would return 2
(where string is '584|521,590|519,594|513,594|513,590|517,594|513,592|517,590|517,594|513,590|519')

Sum of a string of one-digit numbers in javascript?

I'm trying to write a script that adds the left side of a string and validates it against the right side.
For example:
var left = "12345"
var right = "34567"
I need to do some sort of sum function that adds 1+2+3+4+5 and checks if it equals 3+4+5+6+7.
I just don't have a clue how to do it.
I think I need to use a for loop to iterate through the numbers such as
for (var i = 0, length = left.length; i < length; i++)
But I'm not sure how to add each number from there.
EDIT the var is actually being pulled in from a field. so var left = document.blah.blah

DEMO
var left = "12345"
var right = "12345"
function add(string) {
string = string.split(''); //split into individual characters
var sum = 0; //have a storage ready
for (var i = 0; i < string.length; i++) { //iterate through
sum += parseInt(string[i],10); //convert from string to int
}
return sum; //return when done
}
alert(add(left) === add(right));​

Find the length of the string
then in a temp Variable store the value pow(10,length-1)
if you apply module function (left%temp) you will ge the Last significant digit
you can use this digit to add
repeat the process till the length of the string left is 0
6 Repeat all the steps above for the right as well and then compare the values
Note: convert the string to int using parseInt function

var sum = function(a,b){return a+b}
function stringSum(s) {
var int = function(x){return parseInt(x,10)}
return s.split('').map(int).reduce(sum);
}
stringSum(a) == stringSum(b)

Simple JavaScript encryption function

I have a function which has to change characters from one array to the characters from another. It is kind of simple encryption. I have:
var plainArray = ['A','B','C',...,'Z'];
var cipherArray = ['a','b','c',...,'z'];
function rotateToPosition(signalCharacter, indexCharacter, plainAlphabet, cipherAlphabet)
already working.
Now I have to write a function which will change given word into encrypted word.
function encrypt(plainText, signalCharacter, indexCharacter, plainAlphabet, cipherAlphabet)
{
var encryptedString = signalCharacter;
//i is what will hold the results of the encrpytion until it can be appended to encryptedString
var i;
// rotate array to signal character position
var rotateArray = rotateToPosition(signalCharacter, indexCharacter, plainAlphabet, cipherAlphabet);
for (var count = 0; count < plainText.length; count++)
{
plainAlphabet = plainText.charAt(count);
i = cipherAlphabet[plainAlphabet];
encryptedString = encryptedString + rotateArray[i];
}
return encryptedString;
}
This function returns signal character and then a string of errors. Do you know what is wrong?

You are overwriting plainAlphabet with one character, thus discarding the alphabet. I guess that's not what you want.
However, you only posted the signature of rotateToPosition and not the actual code of it, so I cannot test my solution.
function encrypt(plainText, signalCharacter, indexCharacter, plainAlphabet, cipherAlphabet) {
var encryptedString = signalCharacter;
//i is what will hold the results of the encrpytion until it can be appended to encryptedString
var i;
// rotate array to signal character position
var rotateArray = rotateToPosition(signalCharacter, indexCharacter, plainAlphabet, cipherAlphabet);
for (var count = 0; count < plainText.length; count++)
{
var plainLetter = plainText.charAt(count);
i = cipherAlphabet[plainLetter];
encryptedString = encryptedString + rotateArray[i];
}
return encryptedString;
}