An event listener allows your web app to run code based on a users input (among other things). Most event listeners will be created in the [[DOMContentLoaded]] event listener.
# pass arguments to event listeners
An event listener requires a function without parameters, so how do you pass parameters when needed? Simply use an anonymous function to wrap the function with parameters.
```javascript
// Define your function
function myFunction(foo) {
console.log(foo);
}
// Create a variable
let foo = 'bar'
// Use an anonymous function to pass the variable to myFunction
document.getElementById(<id>).addEventListener('change', function() {
myFunction(foo)
})
```
#rough