Use the querySelector() method to check whether a radio button is selected. Programmers can use JavaScript's querySelector() method to select any HTML element. Here, we have used the querySelector() method to select only the checked radio button. If no radio button is selected, it returns a null value.

You can check a radio button by default by adding the checked HTML attribute to the element. You can disable a radio button by adding the disabled HTML attribute to both the and the .

To dynamically select radio button we can use JavaScript checked property, getElementById() method and onclick event.

If you want to assign a checked initial value to your radio button, you can use the HTML checked attribute. In the example below, we use a

Copy Code var getSelectedValue = document.querySelector( 'input[name="season"]:checked'); if(getSelectedValue != null) { document.write("Radio button is selected"); else { document.write("Nothing has been selected");

This process can be automated by looping through an array that contains all the possible values and creating a new radio button element for each item in the array. To dynamically create radio button using an array, use the concept of createElement() and appendChild().

Defining Radio Group in HTML We can define a group for radio buttons by giving each radio button the same name. As and when the user selects a particular option from this group, other options are deselected. Following is an example of radio buttons with different names within a form.