Script for picking up drone's code in Infamous Second Son Paper Trail mission (https://infamouspapertrail.com/dupmodified_trackerdrone)

bruteforce.js

(function() {
	var code = [],
		length = 6,
		exeptions = {},
		shuffle = {},
		freeze = {};

	function generate() {
		for (var i = 0; i < length; i++) {
			var digit = Math.floor(Math.random() * length),
				usedShaffledDigit = false,
				skip = false;

			if (freeze[i]) {
				continue;
			}

			for (var shuffledDigit in shuffle) {
				if (!shuffle[shuffledDigit][i]) {
					digit = shuffledDigit;
					usedShaffledDigit = true;
					break;
				} else if (shuffledDigit == digit) {
					skip = true;
					break;
				}
			}

			if (skip) {
				i--;
				continue;
			}

			if (exeptions[i] && exeptions[i][digit]) {
				if (usedShaffledDigit) {
					shuffle[shuffledDigit][i] = true;
				}
				i--;
				continue;
			}

			code[i] = digit;
		}
	}

	function check() {
		$.get('/pages/guessdiff', {
			guess: code.join('')
		}).done(function(response) {
			if (response.solved) {
				console.info('Succeed attempt! Code: ' + code.join('') + ' Attempts left: ' + response.remaining);
			} else {
				var diffArr = response.diff.split('');

				console.log('Failed attempt! Code: ' + code.join('') + ' Diff: ' + response.diff + ' Attempts left: ' + response.remaining);

				for (var i = 0, length = diffArr.length; i < length; i++) {
					switch(diffArr[i]) {
						case '0':
						case '1':
							if (!exeptions[i]) {
								exeptions[i] = {};
							}
							exeptions[i][code[i]] = true;

							if (diffArr[i] == 1) {
								if (!shuffle[code[i]]) {
									shuffle[code[i]] = {};
								}
								shuffle[code[i]][i] = true;    
							}
							break;
						case '2':
							freeze[i] = true;
							break;
					}
				}
				if (!response.remaining) {
					exeptions = {};
					shuffle = {};
					freeze = {};
					console.log('-----');
				}
				tryAgain();
			}
		});
	}

	function tryAgain() {
		generate();
		check();
	}

	tryAgain();
})();

could your code be altered to use charcacters instead of numbers??