Q:

jQuery - issue referencing radio button with decimal in ID attribute

This is possibly not the best way to do it, but I have a radio button field as follows:
<input type="radio" id="option_3_11_9.95">

along with other radio buttons with similar naming convention, designed to represent different cart options. User submits their selected option and further processing occurs.
However, complication arises if the user wants to return to the selection screen to change their selection, because of the way the ajax/jquery forms/submissions are set up. Long story short, in order to re-select their selected radio button, I currently run a getJSON function which returns data concerning their selected option as follows, and attempts to re-check the appropriate radio button programmatically:
var feature_id = featureID;
$.getJSON("/cfcs/cart.cfc?method=blah&returnformat=json&queryformat=column", {"feature_id":featureID},function(res,code) {
     if(res.ROWCOUNT > 0){
         var price = (Math.round(res.DATA.PRICE*100)/100).toFixed(2).toString(); //ensure 2 decimal places and string
         var option_id = res.DATA.OPTION_ID;
         var str = featureID + "_" + option_id + "_" + price;
         alert(str); // alerts "3_11_9.95"
         alert($("#option_" + str).attr("id")); // alerts "undefined"
         alert($("#option_" + str).attr("checked")); // alerts "undefined"
         $("#option_" + str).attr("checked","checked"); // doesn't work obviously   
     }
})

A:

Escape with \\
$('#option_3_11_9\\.95')

Check Fiddle

