The replaceChild() method is used to replace a node in the node list.

The following code fragment creates the new <book> element that will replace the last <book> element:

Note: Internet Explorer will skip white-space text node that are generated between nodes (e.g. new-line characters), while Mozilla will not. So, in the example above, the get_lastchild() function check the node type of the last child node of the parameter.

Element nodes has the nodeType of 1, so if not the last child of the node in the parameter is an element node, it moves to the previous node, and checks if this node is an element node. This continues until the last child node (which must be the element node) is found. This way, the result will be correct in both Mozilla and Internet Explorer .

The replaceData() method is used to replace data in the text node.

The replaceData() method has three parameter:

• offset - Where to begin replacing character. Offset value starts from zero
• length - How many characters to be replaced
• string - The string value to insert

The following code fragment will replace the eight first character from the text node in the first <title> element with "Easy":