Example

var sentence = document.createTextNode
    ("When you're smiling, the whole world smiles with you.");

In the example above we create a Text node with the value When you're smiling, the whole world smiles with you.. We can then use the substringData method to extract a part of that data.

For example, in the following operation we extract seven characters starting from character offset 12, which returns the substring smiling:

var substring = sentence.substringData(12, 7);

In this next example, the character offset plus character count is larger than the total length of the string, so we'll get everything from the character offset to the end of the string, which is the whole world smiles with you.

var substring = sentence.substringData(21, 999);

The data returned by this method is a simple string — it is not a new Text node.