Validating a radio button is checked with jQuery

Question

On my form I havea set of radio buttons. Here's the mark up:

<div class="optionHolder">
    <p class="optionName">Format</p>
    <div class="option checked">
        <input type="radio" name="fileType" value="avi" />
        <img src="images/avi.png" alt="" />
        <label>AVI</label>
    </div>
    <div class="option">
        <input type="radio" name="fileType" value="mov" />
        <img src="images/mov.png" alt="" />
        <label>MOV</label>
    </div>
    <div class="option">
        <input type="radio" name="fileType" value="mp4" />
        <img src="images/mp4.png" alt="" />
        <label>MP4</label>
    </div>
    <div class="option">
        <input type="radio" name="fileType" value="mp3" />
        <img src="images/mp3.png" alt="" />
        <label>MP3</label>
        </div>
</div>

When the form is submitted I want to check that one of them is checked. What's the best way to go about this? I was thinking of looping through them all and making a flag to set if one of them is checked, and then check the flag after the loop and if it's false throw an error.

Any help is appreciated, cheers.

Answer 1

You can use the length and equal attribute selector with :checked filter selector like this:

if ($("input[name='fileType']:checked").length > 0){
  // one ore more checkboxes are checked
}
else{
 // no checkboxes are checked
}

Answer 2

demo

http://jsfiddle.net/Vq2jB/2/

var isChecked = jQuery("input[name=fileType]:checked").val();