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JavaScript Treehouse Club: JavaScript Car Sounds Background Color, Margin, and Padding

Ming-Tse Ta
Ming-Tse Ta
1,115 Points
Posted by Ming-Tse Ta
Ming-Tse Ta
1,115 Points

img { width: 100%;} .car { display:block; margin: 40px 0 auto 0; why here is "40px 0 auto 0" why put two zero??

img { width: 100%;} .car { display:block; margin: 40px 0 auto 0; why here is "40px 0 auto 0" why ??

css/style.css 
/* Background Color */
html {
  background: #99E6FF;
}


/* Body */
body {
  margin: 0 auto;
  max-width: 800px;
}


/* Images */
img {  width: 100%;}
.car {   display:block;
  margin: 40px 0 auto 0;
  padding: 0;}


/* Links */
a {
  background: transparent;
  border: 0;
  display: block;
  float: left;
  margin: 0;
  outline: 0;
  padding: 0;
  width: 33%; 
}
index.html 
<!DOCTYPE html>
<html lang="en">

  <head>
  <meta name="charset" value="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=0.5, maximum-scale=0.5, minimal-ui">
    <title>Car Sounds</title>

    <!--Style Sheet link-->
    <link rel="stylesheet" type="text/css" href="css/style.css">
  </head>

  <body>

    <!--Car image -->
    <img src="images/bike.png" class="car" alt="car">


    <!--Button-->
    <a href="javascript:bikeBell();"><img src="images/bikeLock.png" alt="key"></a>


    <!--Audio Files-->
    <audio id="bikeBell" src="sounds/bikeBell.mp3" preload="auto"></audio>


    <!--Javascript-->
    <script type="text/javascript">
        function bikeBell() {
            document.getElementById('bikeBell').play();
        }

    </script>

  </body>

</html>

1 Answer

Jason Cook
Jason Cook
11,403 Points
Jason Cook
Jason Cook
11,403 Points

I can probably help clear this up for you. As you know, the margin property can accept four values, defining top, right, bottom, and left margins, respectively. Defining all margins using the single margin property (rather than margin-top, margin-right, etc.) is also known as using the margin shorthand property.

So, below, let's compare the two methods for defining margins, to help show how values are interpreted.

1) Margin - Shorthand Property (as in your example)

margin: 40px 0 auto 0;

2) Margin - Individual Sides

margin-top: 40px;
margin-right: 0;
margin-bottom: auto;
margin-left: 0;

Note: if a top margin or bottom margin is set to "auto", then its inherent value will be interpreted as 0, whereas setting left and right margins to "auto" will cause remaining horizontal space in the element's container to be split equally, and therefore horizontally centering an element within it's parent container (e.g. "margin: 0 auto;").

I hope this helps answer your question, but if you're still curious about learning more, I recommend these two references:

W3Schools - Margins

CSS Tricks - Margins

Happy Coding! Feel free to reply if you have more questions :-)