There are several ways to run JavaScript code in a Python program, but one popular method is to use the PyExecJS library. PyExecJS is a Python library that allows you to run JavaScript code in Python by using the JavaScript engine that is installed on the system.

Here’s an example of how you can use PyExecJS to run JavaScript code in a Python program:

import execjs

# specify the JavaScript code
js_code = """
    function add(a, b) {
        return a + b;
    }
"""

# create a JavaScript runtime
runtime = execjs.get()

# run the JavaScript code
result = runtime.eval(js_code)

# print the result
print(result)

This example first imports the execjs library, then it defines a JavaScript code as a string and creates a JavaScript runtime using the execjs.get() method.

Then it runs the JavaScript code using the eval() method, passing in the string of JavaScript code. The eval() method returns the result of the JavaScript code, which in this case is the function, so it’s not returning any value.

And finally, it prints the result.

It’s also possible to use other libraries like PyV8, PySpiderMonkey, PyNode, PyJs, etc.

Please note that PyExecJs only runs JavaScript on the local machine and it is not a browser JavaScript engine, which means it can’t run browser-specific JavaScript APIs. So if you need to run JavaScript that relies on browser-specific APIs, you will need to use a browser automation library like Selenium or PyAutoGUI.