HTML - checked Attribute

The HTML checked attribute is a boolean attribute that indicates whether a checkbox is checked by default (when the page loads).

We can use the checked attribute with a JavaScript conditional statement to verify whether a checkbox or radio button is checked. It returns true if the checkbox or radio button is checked otherwise;false.

Syntax

Following is the syntax of the HTML checked attribute −

<input type = "checkbox/radio" checked/>

Example

In the following example, we are using the HTML 'checked' attribute inside an input (type='checkbox') element to make it checked by default.

<!DOCTYPE html>
<html lang="en">
<head>
   <title>HTML checked attribute</title>
</head>
<body>
   <!--example of the checked attribute-->
   <form> Select languages that you know: <br>
      <input type="checkbox" checked> Hindi (we used the 'checked' attribute so it is checked by default) <br>
      <input type="checkbox"> English <br>
      <input type="checkbox"> Marathi <br>
      <input type="checkbox"> Telgu
   </form>
</body>
</html>

When we run the above code, it will generate an output consisting of the checkboxes with a default value displayed on the webpage.

Example

Consider the another scenario, where we are going to use the checked attribute with the radio button.

<!DOCTYPE html>
<html lang="en">
<head>
   <title>HTML checked attribute</title>
</head>
<body>
   <!--example of the checked attribute-->
   <form> Choose your gender: <br>
      <input type="radio" name='gender' checked> Male (we used the 'checked' attribute so it is checked by default) <br>
      <input type="radio" name='gender'> Female
   </form>
</body>
</html>

On running the above code, the output window will pop up displaying the radio buttons with a default value on the webpage.

Example

Let's look at the following example, where we are going to run the script to check whether the user has checked a radio button or not.

<!DOCTYPE html>
<html lang="en">
<head>
   <title>HTML checked attribute</title>
</head>
<body>
   <!--example of the checked attribute-->
   <form> Choose your gender: <br>
      <input type="radio" name='gender' value='male' id='m'> Male (we used the 'checked' attribute so it is checked by default) <br>
      <input type="radio" name='gender' value='female' id='f'> Female <br>
      <button onclick="Submit()">Submit</button>
   </form>
   <script>
      function Submit() {
         var m = document.getElementById('m');
         var f = document.getElementById('f');
         if (m.checked == true) {
            alert(m.value);
         } else if (f.checked == true) {
            alert(f.value);
         } else {
            alert("Not checked.");
         }
      }
   </script>
</body>
</html>

When we execute the above script, it will generate an output consisting of the radio buttons on the webpage. when the user tries to click the submit button without checking the radio button it will displays a alert.

html_attributes_reference.htm
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