Postscribe: A Simple and Flexible JavaScript Library for Detecting Changes in the DOM

Postscribe is a JavaScript library that allows you to subscribe to changes in a document, and be notified when those changes occur. It's similar to the `MutationObserver` API, but it's simpler to use and more flexible.

With Postscribe, you can specify a function to call whenever a change is detected, and you can also specify an options object that allows you to customize the behavior of the library. For example, you can use the `childList` option to specify which types of changes you want to detect (e.g., only elements, only attributes, etc.).

Here's an example of how you might use Postscribe to detect changes in a document:
```
const observer = new Postscribe(document, {
childList: true, // detect changes to all children
subtree: true, // detect changes to the entire subtree
attributeOldValue: true // detect changes to attributes
});

observer.onChange = function(change) {
console.log('Change detected:', change);
};
```
In this example, the `Postscribe` instance is created with the `childList`, `subtree`, and `attributeOldValue` options set to `true`. This means that the library will detect changes to all children of the document, as well as changes to the entire subtree, and changes to attributes. The `onChange` function will be called whenever a change is detected.

Postscribe is a useful tool for debugging and testing web applications, as it allows you to easily detect and respond to changes in the DOM. It's also a good choice for applications that need to monitor the state of the DOM over time, such as real-time collaboration tools or data visualization apps.