Question

how to add validation to check whether the user has chosen between two radio buttons? Suppose there are 2 radio buttons; male and female. How can we ensure that the user has selected one of them?

Answer 1

You can use a name for the radio buttons and then use the following

function CheckState()
{
    var rad = document.getElementsByName ( "rdToCheck" );
    var isChecked = false;

    for ( var i = 0;i < rad.length; i++ )
    {
        if ( rad[i].checked == true )
        {
            isChecked = true;
            break;
        }
    }

    if ( !isChecked )
    {
        alert ( "Please select an option" );
    }
}

<input type="radio" id="rd1" name="rdToCheck" />
<input type="radio" id="rd2" name="rdToCheck" />

<button id="btn1" onclick="CheckState();">Click</button>