My JavaScript journey

Day 7 of learning JavaScript: Start Button and Sum

Sven Willhauk's photo
Sven Willhauk
·

3 min read

Today I did a few things on the Blackjack app project. At first, I made the start button display, work and also look good. It was also a very good revision of many things that I have learned so far. I created the button in HTML and told the document to run the JavaScript function "startGame()" when clicked. Then I designed the button a little bit with CSS:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" >
    <meta http-equiv="X-UA-Compatible" content="IE=edge" >
    <meta name="viewport" content="width=device-width, initial-scale=1.0" >
    <title>Blackjack</title>
    <link rel="stylesheet" href="style.css" >
  </head>
  <body>
      <h1>Blackjack</h1>
      <p id="message-el">Want to play a round?</p>
      <p id="cards-el">Cards:</p>
      <p id="sum-el">Sum:</p>
      <button id="start-btn" onclick="startGame()">Start Game</button> <!--When clicked, run function "startGame()" in JS-->
      <script src="index.js"></script>
  </body>
</html>

button{ /*style of the button*/
    width: 150px;
    color: #016f32; 
    background-color: goldenrod;
    padding: 0.25rem;
    border: none;
    border-radius: 3rem;
    font-weight: bold;
}

let firstCard = 11
let secondCard = 11
let sum = firstCard + secondCard
let hasBlackJack = false
let isAlive = true
let message = ""
let messageEl = document.getElementById("message-el") //select the HTML item that contains the message and saves it in a variable

function startGame(){
    if (sum <= 20){
        message = "Do you want to draw a new card?"
        messageEl.textContent = message //Text Content of HTML item = the message
    }
    else if (sum === 21){
        message = "You've got Blackjack!"
        hasBlackJack = true    
        messageEl.textContent = message    //Text Content of HTML item = the message
    }
    else {
        message = "You're out of the game!"
        isAlive = false    
        messageEl.textContent = message    //Text Content of HTML item = the message
    }
}

After this, the Button worked and also the message was updated to the active case.

Then I wanted the sum to display as well. So I also saved the HTML element in a variable called "sumEl" and let the sum display right at the start of the function.

let firstCard = 11
let secondCard = 11
let sum = firstCard + secondCard
let hasBlackJack = false
let isAlive = true
let message = ""
let messageEl = document.getElementById("message-el")
let sumEl = document.getElementById("sum-el") //Select HTML element and saves it.

function startGame(){

    sumEl.textContent = "Sum: " +sum //Display the Sum.
                                     //If the string wasn't there, then it would only display the value of the variable "sum".

    if (sum <= 20){
        message = "Do you want to draw a new card?"
        messageEl.textContent = message
    }
    else if (sum === 21){
        message = "You've got Blackjack!"
        hasBlackJack = true
        messageEl.textContent = message
    }
    else {
        message = "You're out of the game!"
        isAlive = false
        messageEl.textContent = message
    }
}

After this change, the project looked like that:

Today I just used the things I learned previously and revised these things but I hope you guys still learned something valuable.

JavaScriptblackjackWeb Developmentapp developmentLearning Journey