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HTML DOM - How to Change HTML Elements

HTML elements are changed using JavaScript, the HTML DOM and events.

Changing an HTML Element

The HTML DOM and JavaScript can be used to change the inner content and attributes of HTML elements dynamically.

Example 1 - Change the Background Color

The following example changes the background color of the <body> element:

<html>
<body>
<script type="text/javascript">
document.body.bgColor="yellow";
</script>
</body>
</html>

Try it yourself

Changing the Text HTML Element - innerHTML

The easiest way to get or modify the content of an element is by using the innerHTML property.

Example 2 - Change the Text of an Element

The following example changes the text of the <p> element:

<html>
<body>
<p id="p1">Hello World!</p>
<script type="text/javascript">
document.getElementById("p1").innerHTML="New text!";
</script>
</body>
</html>

Try it yourself

Changing an HTML Element Using Events

An event handler allows you to execute code when an event occurs.

Events are generated by the browser when the user clicks an element, when the page loads, when a form is submitted, etc.

You can read more about events in the next chapter.

Example 3 - Change the Background Color Using the onclick Event

The following example changes the background color of the <body> element when the button is clicked:

<html>
<body>

<input type="button" onclick="document.body.bgColor='yellow';"
value="Click me to change background color">

</body>
</html>

Try it yourself

Example 4 - Create a Function to Change the Text of an Element

The following example uses a function to change the text of the <p> element when the button is clicked:

<html>
<head>
<script type="text/javascript">
function ChangeText()
{
document.getElementById("p1").innerHTML="New text!";
}
</script>
</head>

<body>
<p id="p1">Hello world!</p>
<input type="button" onclick="ChangeText()"
value="Click me to change text above">
</body>
</html>

Try it yourself

Using the Style Object

The Style object represents of each HTML element represents its individual style.

The Style object can be accessed from the document or from the elements to which that style is applied.

Example 5 - Change the Background Color

The following example uses a function to change the style of the <body> element when the button is clicked:

<html>
<head>
<script type="text/javascript">
function ChangeBackground()
{
document.body.style.backgroundColor="yellow";
}
</script>
</head>

<body>
<p id="p1">Hello world!</p>
<input type="button" onclick="ChangeBackground()"
value="Click me to change background color">
</body>
</html>

Try it yourself

Example 6 - Change the Text font and color of an Element

The following example uses a function to change the style of the <p> element when the button is clicked:

<html>
<head>
<script type="text/javascript">
function ChangeText()
{
document.getElementById("p1").style.color="blue";
document.getElementById("p1").style.fontFamily="Arial";
}
</script>
</head>

<body>
<p id="p1">Hello world!</p>
<input type="button" onclick="ChangeText()"
value="Click me to change text above">
</body>
</html>

Try it yourself