如何找到一组单选按钮的值？

I have a function which loops through a form and finds the values of each element, for example, checkboxes, input fields etc. as it loops through the tags of this form it adds them onto a string, for example, if I had a select tag with several option tags inside of it, it would take the value of the select tag, which is conveniently the currently selected value of the select tag, and add it to the string.I have a function which loops through a form an