diff --git a/szamrendszer.js b/szamrendszer.js
index eba2ecb..69ad5a5 100644
--- a/szamrendszer.js
+++ b/szamrendszer.js
@@ -1,174 +1,62 @@
-$(document).ready(function(){
-	var inputNumber = 0;
-	var selectedOption = "";
-	var answer = 0;
+document.addEventListener("DOMContentLoaded", function () {
+    const inputValue = document.getElementById("érték");
+    const inputBase = document.getElementById("bevitel");
+    const outputBase = document.getElementById("kimenet");
+    const outputValue = document.getElementById("kiszámoltérték");
+    const convertButton = document.getElementById("számolás");
+    const swapButton = document.getElementById("felcserélés");
 
-	$("#inputNumber").keyup(function(){
-		inputNumber = $(this).val();
-		setAnswer("");
-		activeDieactiveBtn();
-	})
-	$("#fromTo").change(function(){
-		selectedOption = $(this).val();
-		activeDieactiveBtn();
-	})
-	
-	
-	$("#convertBtn").click(function(){
-		if(selectedOption == "decimal to binary" && inputNumber != ""){
-			answer = convertDecimalToBinary(inputNumber);
-			setAnswer(answer);
-		}else if(selectedOption == "binary to decimal" && inputNumber != ""){
-			answer = convertBinaryToDecimal(inputNumber);
-			setAnswer(answer);
-		}else if(selectedOption == "decimal to hexadecimal" && inputNumber != ""){
-			answer = convertDecimalToHexadecimal(inputNumber);
-			setAnswer(answer);
-		}else if(selectedOption == "hexadecimal to decimal" && inputNumber != ""){
-			answer = convertHexadecimalToDecimal(inputNumber);
-			setAnswer(answer);
-		}else if(selectedOption == "binary to hexadecimal" && inputNumber != ""){
-			var decimalVal = convertBinaryToDecimal(inputNumber);
-			answer = convertDecimalToHexadecimal(decimalVal);
-			setAnswer(answer);
-		}else if(selectedOption == "hexadecimal to binary" && inputNumber != ""){
-			var decimalVal = convertHexadecimalToDecimal(inputNumber);
-			answer = convertDecimalToBinary(decimalVal);
-			setAnswer(answer);
-		}else{
-			resetAll();
-		}
-	})
-	
-	$("#resetBtn").click(function(){
-		resetAll();
-	})
-	
-})
+    function convertNumber(value, fromBase, toBase) {
+        let decimalValue;
+        
+        // Convert input to decimal first
+        switch (fromBase) {
+            case "bináris":
+                decimalValue = parseInt(value, 2);
+                break;
+            case "oktális":
+                decimalValue = parseInt(value, 8);
+                break;
+            case "decimális":
+                decimalValue = parseInt(value, 10);
+                break;
+            case "hexadecimális":
+                decimalValue = parseInt(value, 16);
+                break;
+            default:
+                return "Hibás bemenet";
+        }
+        
+        if (isNaN(decimalValue)) {
+            return "Érvénytelen szám";
+        }
+        
+        // Convert decimal to target base
+        switch (toBase) {
+            case "bináris":
+                return decimalValue.toString(2);
+            case "oktális":
+                return decimalValue.toString(8);
+            case "decimális":
+                return decimalValue.toString(10);
+            case "hexadecimális":
+                return decimalValue.toString(16).toUpperCase();
+            default:
+                return "Hibás átváltás";
+        }
+    }
 
-function activeDieactiveBtn(){
-	
-	var inputNumber = $("#inputNumber").val();
-	var selectedOption = $("#fromTo").val();
-	
-	if(inputNumber != "" && selectedOption != ""){
-		$("#convertBtn").prop("disabled",false);
-	}else{
-		$("#convertBtn").prop("disabled",true);
-	}
-	
-	if(inputNumber != "" || selectedOption != ""){
-		$("#resetBtn").prop("disabled",false);
-	}else{
-		$("#resetBtn").prop("disabled",true);
-	}
-	
-}
+    convertButton.addEventListener("click", function () {
+        const value = inputValue.value.trim();
+        const fromBase = inputBase.value;
+        const toBase = outputBase.value;
+        
+        outputValue.value = convertNumber(value, fromBase, toBase);
+    });
 
-function setAnswer(answer){
-	$("#showAnswer").html(answer);
-}
-
-function resetAll(){
-		$("#convertBtn").prop("disabled",true);
-		$("#showAnswer").html("");
-		$("#inputNumber").val("");
-		$("#fromTo").val("").change();
-		$(this).prop("disabled",true);
-}
-
-
-// main functions
-function convertDecimalToBinary(inputNumber){
-	var answer = "";
-	if(!isNaN(inputNumber)){
-		inputNumber = Number(inputNumber);
-		var remainder = 0;
-		while(inputNumber != 0){
-			remainder = inputNumber % 2;
-			inputNumber = ((inputNumber - remainder) / 2);
-			answer = remainder + answer;
-		}
-	}else{
-		answer = '<span style="color: red;">This is not decimal number!</span>';
-	}
-	return answer;
-}
-
-function convertBinaryToDecimal(inputNumber){
-	inputNumber = inputNumber.toString();
-	var numberLen = inputNumber.length;
-	var position = numberLen;
-	var answer = 0;
-	for(var i = 0; i < numberLen; i++){
-		if(inputNumber[i] == '0' || inputNumber[i] == '1'){
-			position--;
-			answer = answer + (   Number(inputNumber[i]) *  Math.pow(2, position) );
-		}else{
-			answer = '<span style="color: red;">This is not binary number!</span>';
-		}
-	}
-	return answer;
-}
-
-function convertDecimalToHexadecimal(inputNumber){
-	inputNumber = Number(inputNumber);
-	var remainder = 0;
-	var answer = "";
-	if(!isNaN(inputNumber)){
-			inputNumber = Number(inputNumber);
-			while(inputNumber != 0){
-			remainder = inputNumber % 16;
-			inputNumber = ((inputNumber - remainder) / 16);
-			if(remainder == 10){
-				answer = 'A' + answer;
-			}else if(remainder == 11){
-				answer = 'B' + answer;
-			}else if(remainder == 12){
-				answer = 'C' + answer;
-			}else if(remainder == 13){
-				answer = 'D' + answer;
-			}else if(remainder == 14){
-				answer = 'E' + answer;
-			}else if(remainder == 15){
-				answer = 'F' + answer;
-			}else{
-				answer =  remainder + answer;
-			}
-		}
-	}else{
-		answer = '<span style="color: red;">This is not decimal number!</span>';
-	}
-	return answer;
-}
-
-function convertHexadecimalToDecimal(inputNumber){
-	inputNumber = inputNumber.toString();
-	var numberLen = inputNumber.length;
-	var position = numberLen;
-	var answer = 0;
-	for(var i = 0; i < numberLen; i++){
-		var num = inputNumber[i];
-		if(num == 'A'){
-			num = 10;
-		}else if(num == 'B'){
-			num = 11;
-		}else if(num == 'C'){
-			num = 12;
-		}else if(num == 'D'){
-			num = 13;
-		}else if(num == 'E'){
-			num = 14;
-		}else if(num == 'F'){
-			num = 15;
-		}else if(num >= '0' && num <= '9'){
-			num = Number(num);
-		}else{
-			answer = '<span style="color: red;">This is not Hexadecimal number!</span>';
-			return answer;
-		}
-		position--; 
-		answer = answer + (num* Math.pow(16,position));
-	}
-	return answer;
-}   
\ No newline at end of file
+    swapButton.addEventListener("click", function () {
+        const tempValue = inputBase.value;
+        inputBase.value = outputBase.value;
+        outputBase.value = tempValue;
+    });
+});
\ No newline at end of file