how to know which radio button is selected javascript

The easiest way to know which radio button is selected in JavaScript is to use the `.checked` property. This property is a boolean value that is true when the radio button is checked and false when the radio button is not checked. Here is an example of how to check if a radio button is selected: ``` Option 1 Option 2  let selected = document.querySelector('input[name="example"]:checked').value; console.log(selected); ``` In the example above, we use the `document.querySelector()` method to select the radio button with the name attribute of "example" that has been checked. Then we use the `.value` property to get the value of the selected radio button. You can also use the `.checked` property to check if a radio button is selected without having to select the radio button. Here is an example: ``` Option 1 Option 2  let option1 = document.querySelector('input[name="example"][value="1"]').checked; let option2 = document.querySelector('input[name="example"][value="2"]').checked; console.log(option1); console.log(option2); ``` In the example above, we use the `document.querySelector()` method to select the radio button with the name attribute of "example" and the value attribute of "1" or "2". Then we use the `.checked` property to determine if the radio button is selected or not. You can also use the `.addEventListener()` method to detect when a radio button is selected. Here is an example: ``` Option 1 Option 2  let radios = document.querySelectorAll('input[name="example"]'); radios.forEach((radio) => { radio.addEventListener('change', (e) => { let selected = e.target.value; console.log(selected); }); }); ``` In the example above, we use the `document.querySelectorAll()` method to select all the radio buttons with the name attribute of "example". Then we use the `.addEventListener()` method to detect when a radio button is selected and get the value of the selected radio button. Hopefully this helps you understand how to determine which radio button is selected in JavaScript.