The HTML DOM insertBefore() method inserts a new node before an already existing child node.
Syntax
Following is the syntax −
Calling insertBefore() with parameters of positionString and text
node.insertBefore(newNode, existingNode)
Here, parameters can be the following −
Parameters
| parameters | Description |
|---|---|
| newNode | It is the newly created child node which is to be appended at beginning |
| existingNode | It is the already existing node |
Example
Let us see an example for InsertBefore() method −
<!DOCTYPE html>
<html>
<head>
<title>insertBefore()</title>
<style>
form {
width:70%;
margin: 0 auto;
text-align: center;
}
* {
padding: 2px;
margin:5px;
}
input[type="button"] {
border-radius: 10px;
}
ol {
width:30%;
margin: 0 auto;
}
</style>
</head>
<body>
<form>
<fieldset>
<legend>insertBefore( )</legend>
<h1>How to make tea</h1>
<h3>Steps:</h3>
<ol id="stepList">
<li>Add Tea Bag</li>
<li>Add Sugar</li>
<li>Add Milk</li>
</ol>
<input type="button" onclick="addStep()" value="Add">
</fieldset>
</form>
<script>
function addStep() {
var newIngredient = document.createElement("LI");
var textnode = document.createTextNode("Boil Water");
newIngredient.appendChild(textnode);
var stepList = document.getElementById("stepList");
stepList.insertBefore(newIngredient, stepList.childNodes[0]);
}
</script>
</body>
</html>Output
This will produce the following output −
Before clicking ‘Add’ button −
After clicking ‘Add’ button −
