JavaScript native code takes the value of a radio box

Online search, the project is just used, first note down, and then directly from their own blog copy and paste!!!

The Namefunction getradioboxvalue (radioname) {var obj = Document.getelementsbyname (radioname) of the incoming radio box is taken from the selected value in the selection box. This is the name of the tag to fetch the control for (i = 0; i < obj.length; i++) {
if (obj[i].checked) {return obj[i].value;
}
}return "undefined";
}

JavaScript native code takes the value of a radio box