HTML | DOM Style boxSizing Property

Difficulty Level : Basic
Last Updated : 31 Jul, 2019

The DOM Style boxSizing property is used to set or return how an object should be made to fit an element taking into consideration it’s padding, border and content.
This property can be useful when fitting elements into their desired position by automatically calculating their dimensions.

Syntax:

It returns the boxSizing Property:
```
object.style.boxSizing
```

It is used to set the boxSizing Property:

object.style.boxSizing = "border-box | content-box | initial | 
inherit"

Property Values:

border-box: Using this value, any padding or border specified on the element is included and drawn inside the specified width and height. The dimensions of the content are calculated by subtracting the border and padding from the specified ‘width’ and ‘height’ properties of the element itself.

Example-1:

<!DOCTYPE html>
<html>
  
<head>
    <title>
      DOM Style boxSizing Property
    </title>
    <style>
        .container {
            width: 200px;
            height: 300px;
            border: 10px solid green;
        }
          
        .box {
            width: 200px;
            height: 100px;
            border: 5px solid lightgreen;
            text-align: center;
            font-size: 2rem;
        }
    </style>
</head>
  
<body>
    <h1 style="color: green">
      GeeksForGeeks
    </h1>
    <b>
      DOM Style boxSizing Property
    </b>
    <p>
      The container element has a
      height of 500px and width of 200px.
        <br>The boxes inside have a height
      of 100px and width of 200px.
    </p>
    <div class="container">
        <div class="box" 
             id="box-1">
          Geeks
      </div>
        <div class="box"
             id="box-2"
             style="padding: 10px;">
          For
      </div>
        <div class="box"
             id="box-3">
          Geeks
      </div>
    </div>
  
    <p>
      Click the button to set the boxSizing 
      property of the three boxes to 
      border-box.
    </p>
    <button onclick="setBoxSizing()">
      Change boxSizing
    </button>
    <script>
        function setBoxSizing() {
            
            document.getElementById(
              "box-1").style.boxSizing =
              "border-box";
            
            document.getElementById(
              "box-2").style.boxSizing = 
              "border-box";
            
            document.getElementById(
              "box-3").style.boxSizing = 
              "border-box";
        }
    </script>
</body>
  
</html>

Output:

Before clicking the button:
border-box-before

After clicking the button:
border-box-after

content-box: Using this value, the specified width and height are applied to content-box of the element. Any padding and border specified on the element are added and drawn outside the specified dimensions of the box. This is the default value.

Example-2:

<!DOCTYPE html>
<html>
  
<head>
    <title>
      DOM Style boxSizing Property
    </title>
    <style>
        .container {
            width: 200px;
            height: 300px;
            border: 10px solid green;
        }
          
        .box {
            width: 200px;
            height: 100px;
            border: 5px solid lightgreen;
            text-align: center;
            font-size: 2rem;
            box-sizing: border-box;
        }
    </style>
</head>
  
<body>
    <h1 style="color: green">
      GeeksForGeeks
    </h1>
    <b>
      DOM Style boxSizing Property
    </b>
    <p>
      The container element has a height 
      of 500px and width of 200px.
        <br>The boxes inside have a height
      of 100px and width of 200px.
    </p>
    <div class="container">
        <div class="box" 
             id="box-1">
          Geeks
      </div>
        <div class="box" 
             id="box-2"
             style="padding: 10px;">
          For
      </div>
        <div class="box" 
             id="box-3">
          Geeks
      </div>
    </div>
  
    <p>
      Click the button to set the boxSizing
      property of the three boxes to 
      content-box.
    </p>
  
    <button onclick="setBoxSizing()">
      Change boxSizing
    </button>
  
    <script>
        function setBoxSizing() {
            
            document.getElementById(
              "box-1").style.boxSizing = "content-box";
            document.getElementById(
              "box-2").style.boxSizing = "content-box";
            document.getElementById(
              "box-3").style.boxSizing = "content-box";
        }
    </script>
</body>
  
</html>

Output:
Before clicking the button:
content-box-before

After clicking the button:
content-box-after

initial: This is used to set this property to its default value.

Example-3:

<!DOCTYPE html>
<html>
  
<head>
    <title>
      DOM Style boxSizing Property
    </title>
    <style>
        .container {
            width: 200px;
            height: 300px;
            border: 10px solid green;
        }
          
        .box {
            width: 200px;
            height: 100px;
            border: 5px solid lightgreen;
            text-align: center;
            font-size: 2rem;
            box-sizing: border-box;
        }
    </style>
</head>
  
<body>
    <h1 style="color: green">
      GeeksForGeeks
    </h1>
    <b>
      DOM Style boxSizing Property
    </b>
    <p>
      The container element has a height 
      of 500px and width of 200px.
        <br>The boxes inside have a height
      of 100px and width of 200px.
    </p>
    <div class="container">
        <div class="box" 
             id="box-1">
          Geeks
      </div>
        <div class="box" 
             id="box-2"
             style="padding: 10px;">
          For
      </div>
        <div class="box"
             id="box-3">
          Geeks
      </div>
    </div>
  
    <p>
      Click the button to set the boxSizing 
      property of the three boxes to initial.
    </p>
    <button onclick="setBoxSizing()">
      Change boxSizing
    </button>
    <script>
        function setBoxSizing() {
            
            document.getElementById(
              "box-1").style.boxSizing = "initial";
            
            document.getElementById(
              "box-2").style.boxSizing = "initial";
            
            document.getElementById(
              "box-3").style.boxSizing = "initial";
        }
    </script>
</body>
  
</html>

Output:
Before clicking the button:
initial-before

After clicking the button:
initial-after

inherit: This inherits the property from its parent.

Example-4:

<!DOCTYPE html>
<html>
  
<head>
    <title>
      DOM Style boxSizing Property
    </title>
    <style>
        .container {
            width: 200px;
            height: 300px;
            border: 10px solid green;
            /* this acts as the parent */
            box-sizing: border-box;
        }
          
        .box {
            width: 200px;
            height: 100px;
            border: 5px solid lightgreen;
            text-align: center;
            font-size: 2rem;
        }
    </style>
</head>
  
<body>
    <h1 style="color: green">
      GeeksForGeeks
    </h1>
    <b>
      DOM Style boxSizing Property
    </b>
    <p>
      The container element has a 
      height of 500px and width of 200px.
        <br>The boxes inside have a 
      height of 100px and width of 200px.
    </p>
    <div class="container">
        <div class="box" 
             id="box-1">
          Geeks
      </div>
        <div class="box" 
             id="box-2" 
             style="padding: 10px;">
          For
      </div>
        <div class="box" 
             id="box-3">
          Geeks
      </div>
    </div>
    <p>
      Click the button to set the boxSizing
      property of the three boxes to inherit.
    </p>
    <button onclick="setBoxSizing()">
      Change boxSizing
    </button>
    <script>
        function setBoxSizing() {
            
            document.getElementById(
              "box-1").style.boxSizing = "inherit";
            
            document.getElementById(
              "box-2").style.boxSizing = "inherit";
            
            document.getElementById(
              "box-3").style.boxSizing = "inherit";
        }
    </script>
</body>
  
</html>