jquery radio button group set checked code example
Example: radio button group html jquery
<input type="radio" id="radio1" name="RadioGroup1" value="1" checked="true"/>
<input type="radio" id="radio2" name="RadioGroup1" value="2" />
<input type="radio" id="radio3" name="RadioGroup1" value="3" />
//in your jquery
var value = $("input[name=RadioGroup1]:checked").val();
alert("The user selected; " + value);