How can I check whether a radio button is selected

Question

I have two radio buttons within an HTML form. A dialog box appears when one of the fields is null. How can I check whether a radio button is selected?

Answer 1

I just want to ensure something gets selected (using jQuery):

// html
<input name="gender" type="radio" value="M" /> Male <input name="gender" type="radio" value="F" /> Female

// gender (required)
var gender_check = $('input:radio[name=gender]:checked').val();
if ( !gender_check ) {
    alert("Please select your gender.");
    return false;
}

Answer 2

Note this behavior wit jQuery when getting radio input values:

$('input[name="myRadio"]').change(function(e) { // Select the radio input group

    // This returns the value of the checked radio button
    // which triggered the event.
    console.log( $(this).val() ); 

    // but this will return the first radio button's value,
    // regardless of checked state of the radio group.
    console.log( $('input[name="myRadio"]').val() ); 

});

So $('input[name="myRadio"]').val() does not return the checked value of the radio input, as you might expect -- it returns the first radio button's value.

Answer 3

You can use this simple script. You may have multiple radio buttons with same names and different values.

var checked_gender = document.querySelector('input[name = "gender"]:checked');

if(checked_gender != null){  //Test if something was checked
alert(checked_gender.value); //Alert the value of the checked.
} else {
alert('Nothing checked'); //Alert, nothing was checked.
}

Answer 4

An example:

if (!checkRadioArray(document.ExamEntry.level)) { 
    msg+="What is your level of entry? \n"; 
    document.getElementById('entry').style.color="red"; 
    result = false; 
} 

if(msg==""){ 
    return result;  
} 
else{ 
    alert(msg) 
    return result;
} 

function Radio() { 
    var level = radio.value; 
    alert("Your level is: " + level + " \nIf this is not the level your taking then please choose another.") 
} 

function checkRadioArray(radioButtons) { 
    for(var r=0;r < radioButtons.length; r++) { 
        if (radioButtons[r].checked) { 
            return true; 
        } 
    } 
    return false; 
} 

Answer 5

Just trying to improve on Russ Cam's solution with some CSS selector sugar thrown in with the vanilla JavaScript.

var radios = document.querySelectorAll('input[type="radio"]:checked');
var value = radios.length>0? radios[0].value: null;

No real need for jQuery here, querySelectorAll is widely supported enough now.

Edit: fixed a bug with the css selector, I've included the quotes, although you can omit them, in some cases you can't so it's better to leave them in.

Answer 6

With JQuery, another way to check the current status of the radio buttons is to get the attribute 'checked'.

For Example:

<input type="radio" name="gender_male" value="Male" />
<input type="radio" name="gender_female" value="Female" />

In this case you can check the buttons using:

if ($("#gender_male").attr("checked") == true) {
...
}