Using JavaScript to Check a Radio Button

By Daztech February 26, 2024

1 Min Read

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We can use JavaScript to check a radio button by making use of the getElementById() method along with targeting the checked property value. We simply need to change the checked property value of the radio button to true. Here is how we can do this:

document.getElementById("radioButton").checked = true;

Let’s see an example of this below.

---

Lets say we have the following HTML:

  
Select your favorite mode of transportation:
   Bike

   Car

   Bus

   Train

   Boat

   Airplane


  
Set the radio button Airplane to checked

In this example, we will use the onclick event to call a function setRadio() which we will create below.

The setRadio() function will simply set the last radio button, Airplane, to be checked.

Here is our function using JavaScript:

function setRadio(){
  document.getElementById("airplane").checked = true;
}; 

Let’s try this out below:

Code Output:

Select your favorite mode of transportation:

Bike
Car
Bus
Train
Boat
Airplane

Set the radio button Airplane to checked

Full Code:

  
Select your favorite mode of transportation:
   Bike

   Car

   Bus

   Train

   Boat

   Airplane


  
Set the radio button Airplane to checked

To uncheck a button using JavaScript, we simply need to set the checked attribute to false.

Using JavaScript to Get the Value of a Radio Button

We can use JavaScript to get the value of a radio button using the querySelector() method.

document.querySelector('input[name="radio1"]:checked').value;

Lets say we have the following HTML:

  
Select your favorite mode of transportation:
  Bike

  Car

  Bus

  Train

  Boat

  Airplane

In this example, the checked radio button to start will be the Train option. We can use our code above to get this value using JavaScript.

Here is the jQuery code we will need:

var selectedRadioButton = document.querySelector('#div2 input[name="transport"]:checked').value;

Try it out below by selecting a radio button and then clicking the button below to see what radio button is checked:

Code Output:

Full Code:

  
Select your favorite mode of transportation:
   Bike

   Car

   Bus

   Train

   Boat

   Airplane


  
Check which radio button is selected with JavaScript