Converting the size of an object to megabytes (MB) in JavaScript can be achieved by following a few simple steps. First, calculate the total size of the object in bytes using the JSON.stringify method to convert the object to a JSON string. Then, divide the total size by 1024*1024 to obtain the size in megabytes. Here's a sample code snippet to demonstrate the conversion:

```javascript

// Sample object

const obj = {

key1: 'value1',

key2: 'value2'

};

// Convert object to JSON string and get its size in bytes

const jsonString = JSON.stringify(obj);

const byteSize = new Blob([jsonString]).size;

// Convert byte size to megabytes

const mbSize = byteSize / (1024 * 1024);

console.log('Size of the object in megabytes:', mbSize);

```

By following these steps, you can easily convert the size of any object to megabytes in JavaScript. This can be particularly useful when you need to check the size of an object before performing certain operations, or when you need to limit the size of an object being processed or transmitted over a network.