script.js

var englishTextbox = document.getElementById("englishTextbox");
var alienTextbox = document.getElementById("alienTextbox");
var languageSelector = document.getElementById("alienLanguage")

englishTextbox.onkeyup = function() {engToAl()}
alienTextbox.onkeyup = function() {alToEng()}
languageSelector.onchange = function() {engToAl()}

function engToAl()
{
	var englishString = englishTextbox.value;
	var wordLength = 0 //Initializing before the loop
	var alienString = "" //Initializing before the loop
	for(i = 0; i <= englishString.length - 1; i++) //We want to separate the different words, translate them, then restore them with all the characters around
	{
		if (englishString[i].match(/[a-z]/i)) //Is it a letter?
		{
			wordLength++ //If it is, then the word is a bit longer
		}
		else //Otherwise, we reached the end of the word
		{
			if (wordLength == 0) //This is to correctly restore subsequent non-letter characters
			{
				alienString = alienString + englishString[i]
			}
			else
			{
				englishWord = englishString.substring(i - wordLength, i) //It's not a letter, the word ended. Let's translate it
				alienWord = translateEnglishToAlien(englishWord)
				if (alienWord == undefined)
				{
					alienString = alienString + englishWord //If it's not a translatable word, we'll keep the original, like Google translate does
				}
				else
				{
					alienString = alienString + alienWord
				}
				alienString = alienString + englishString[i] //Let's not forget the non-letter character that made us stop
				wordLength = 0 //The word ended, let's start counting again
			}
		}
		if (i == englishString.length - 1) //Verification for the last word, let's not forget to process it
		{
			if (englishString[i].match(/[a-z]/i))
			{
				englishWord = englishString.substring(i - wordLength + 1, i + 1)
				translateEnglishToAlien(englishWord)
				alienWord = translateEnglishToAlien(englishWord)
				if (alienWord == undefined)
				{
					alienString = alienString + englishWord //If it's not a translatable word, we'll keep the original, like Google translate does
				}
				else
				{
					alienString = alienString + alienWord
				}
			}
		}
	}
	alienTextbox.value = alienString
};

function translateEnglishToAlien(word)
{
	switch (languageSelector.value) //Which language do you want to translate it to?
	{
		case "Korvax":
			return(engToKorvax[word]);
			break;
		case "Gek":
			return(engToGek[word]);
			break;
		case "Vy'keen":
			return(engToVykeen[word]);
			break;
		case "Atlas":
			return(engToAtlas[word]);
			break;
		default:
			console.error("Hey, you changed something with the alien languages, it doesn't work anymore");
			return("???");
	}
}

function alToEng()
{
	var alienString = alienTextbox.value;
	var wordLength = 0 //Initializing before the loop
	var englishString = "" //Initializing before the loop
	for(i = 0; i <= alienString.length - 1; i++) //We want to separate the different words, translate them, then restore them with all the characters around
	{
		if (alienString[i].match(/[a-z]/i)) //Is it a letter?
		{
			wordLength++ //If it is, then the word is a bit longer
		}
		else //Otherwise, we reached the end of the word
		{
			if (wordLength == 0) //This is to correctly restore subsequent non-letter characters
			{
				englishString = englishString + alienString[i]
			}
			else
			{
				alienWord = alienString.substring(i - wordLength, i) //It's not a letter, the word ended. Let's translate it
				englishWord = translateAlienToEnglish(alienWord)
				if (englishWord == undefined)
				{
					englishString = englishString + alienWord //If it's not a translatable word, we'll keep the original, like Google translate does
				}
				else
				{
					englishString = englishString + englishWord
				}
				englishString = englishString + alienString[i] //Let's not forget the non-letter character that made us stop
				wordLength = 0 //The word ended, let's start counting again
			}
		}
		if (i == alienString.length - 1) //Verification for the last word, let's not forget to process it
		{
			if (alienString[i].match(/[a-z]/i))
			{
				alienWord = alienString.substring(i - wordLength + 1, i + 1)
				translateAlienToEnglish(alienWord)
				englishWord = translateAlienToEnglish(alienWord)
				if (englishWord == undefined)
				{
					englishString = englishString + alienWord //If it's not a translatable word, we'll keep the original, like Google translate does
				}
				else
				{
					englishString = englishString + englishWord
				}
			}
		}
	}
	englishTextbox.value = englishString
};

function translateAlienToEnglish(word)
{
	switch (languageSelector.value) //Which language do you want to translate it from?
	{
		case "Korvax":
			return(korvaxToEng[word]);
			break;
		case "Gek":
			return(gekToEng[word]);
			break;
		case "Vy'keen":
			return(vykeenToEng[word]);
			break;
		case "Atlas":
			return(atlasToEng[word]);
			break;
		default:
			console.error("Hey, you changed something with the alien languages, it doesn't work anymore");
			return("???");
	}
}