In this tutorial we will learn How To Check if Radio Button is Checked or Not with JavaScript. JavaScript querySelectorAll() method and checked property are used to check the radio button state.
Table of Contents
querySelectorAll() method
JavaScript querySelectorAll() method selects or targets the HTML elements who match with the CSS selector used.
In this example querySelectorAll() method is used to select all radio buttons with the help of name.
checked property
JavaScript checked property either checks or unchecks the radio button or HTML checkbox or it is used to check the current state of these two input elements.
In this example checked property is used to check if radio button is checked or not.
HTML Code
HTML Code is given below, in this code we have two radio buttons with two labels and a button tag with onclick event to execute a JavaScript function.
<!DOCTYPE html>
<html>
<head>
<title>JavaScript Check if Radio Button is Checked or Not</title>
</head>
<body>
<label for="m1">Male</label>
<input type="radio" id="m1" value="male" name="gender">
<label for="f1">Female</label>
<input type="radio" id="f1" value="female" name="gender">
<button onclick='checkRadio()'>Check Radio Button</button>
<script src="script.js"></script>
</body>
</html>
JavaScript Code
Take a look at the JavaScript code, in this code querySelectorAll() method is used to select the radio button with name = gender.
Since there are more than one radio button so we have used for loop to check all radio buttons if they are checked or not.
The loop will break if any radio button is found checked. This is done using break statement to make sure that the alert message is only displayed once. At the same time value of variable a is changed to make sure that second if block doesn't execute.
If the value of a doesn't change and remains 0, then it means none of the radio buttons is checked and all are unchecked. Thus the related message (in second if statement) will be displayed.
<script>
var a=0;
const radio = document.querySelectorAll('input[name="gender"]');
function checkRadio()
{
for (var i = 0; i < radio.length; i++)
{
if (radio[i].checked)
{
alert('Checked!');
a =1;
break;
}
}
if(a==0)
{
alert('Not Checked!');
}
}
</script>
Demo
Video Tutorial
Watch video tutorial on How To Check if Radio Button is Checked or Not in JavaScript.