First, your html seems malformed, why are there body tags inside of spans.
Second, are you sure there is an html element on the page with the id 'RefreshMapping'? Verify that is the result of if you are trying to get this radio button.
Third, the value for your input is currently set to "true" via 'value="true"', to select a radio button in javascript you must set the element to checked. This will give the property specified in the name attribute the value of the inputs' value attribute. Radio buttons usually have multiple input tags to the same radiobutton group, in order to select a button in that group, you get that specific element and set it to checked via document.getElementByID("id").checked = "true";