check radio button is checked using JQuery

Given a group of radio buttons:

<input type="radio" id="radio1" name="radioGroup" value="1">
<input type="radio" id="radio2" name="radioGroup" value="2">

You can test whether a specific one is checked using jQuery as follows:

if ($("#radio1").prop("checked")) {
   // do something
}

// OR
if ($("#radio1").is(":checked")) {
   // do something
}

// OR if you don't have ids set you can go by group name and value
// (basically you need a selector that lets you specify the particular input)
if ($("input[name='radioGroup'][value='1']").prop("checked"))