Javasipt: Detailed explanation of operation radio tags

1. HTML code:

Copy the codeThe code is as follows:

<input type="radio" name="opinionCategory" value="1" checked /> Most agree
<input type="radio" name="opinionCategory" value="0" /> Most disagree

</form>

2. js code:
Method 1:

Copy the codeThe code is as follows:

var opinionCategory = ('opinionCategory');

                 var opinionCategoryValue = 1;
                 for(var i=0;i<;i++){
                        if(opinionCategory[i].checked){
                                      opinionCategoryValue = opinionCategory[i].value;
                        }
                 }

Method 2:

Copy the codeThe code is as follows:

var form = ('userOpinionForm');

                 var num = 0;
                 for(var i=0;i<;i++){
                     if([i].checked){
                         num++;
                     }
                 }