JavaScript HTML DOM - Changing HTML
The HTML DOM allows JavaScript to change the content of HTML elements.
Changing the HTML Output Stream
JavaScript can create dynamic HTML content:Date: Sat Nov 25 2017 10:41:58 GMT-0800 (Pacific Standard Time)
In JavaScript, document.write() can be used to write directly to the HTML output stream:
Example
<!DOCTYPE html>
<html>
<body>
<script>
document.write(Date());
</script>
</body>
</html> Never use document.write() after the document is loaded. It will overwrite the document.
Changing HTML Content
The easiest way to modify the content of an HTML element is by using the innerHTML property.To change the content of an HTML element, use this syntax:
document.getElementById(id).innerHTML = new HTMLThis example changes the content of a <p> element:Example
<html>
<body>
<p id="p1">Hello World!</p>
<script>
document.getElementById("p1").innerHTML = "New text!";
</script>
</body>
</html> - The HTML document above contains a <p> element with id="p1"
- We use the HTML DOM to get the element with id="p1"
- A JavaScript changes the content (innerHTML) of that element to "New text!"
Example
<!DOCTYPE html>
<html>
<body>
<h1 id="id01">Old Heading</h1>
<script>
var element = document.getElementById("id01");
element.innerHTML = "New Heading";
</script>
</body>
</html> - The HTML document above contains an <h1> element with id="id01"
- We use the HTML DOM to get the element with id="id01"
- A JavaScript changes the content (innerHTML) of that element to "New Heading"
Changing the Value of an Attribute
To change the value of an HTML attribute, use this syntax:document.getElementById(id).attribute = new valueThis example changes the value of the src attribute of an <img> element:Example
<!DOCTYPE html>
<html>
<body>
<img id="myImage" src="smiley.gif">
<script>
document.getElementById("myImage").src = "landscape.jpg";
</script>
</body>
</html> - The HTML document above contains an <img> element with id="myImage"
- We use the HTML DOM to get the element with id="myImage"
- A JavaScript changes the src attribute of that element from "smiley.gif" to "landscape.jpg"
