app.py

import streamlit as st
import streamlit.components.v1 as components

# Define the JavaScript code
js_code = """
function myFunction() {
    // Perform your desired operation here
    var result = "This is the result from JavaScript";
    return result;
}
"""

# Create a custom component with the JavaScript code
mycomponent = components.declare_component("mycomponent", js_code)

# Add a button to trigger the JavaScript function
if st.button("Run JavaScript Function"):
    result = mycomponent()
    st.markdown(f"The result is: {result}")