Magento 1 - Review Stars - Prototype

ReviewStars.js

document.observe('dom:loaded', function(){
    $$('#product-review-table td input').each(function(el){
        el.observe('click', function(ev){
            var attr = el.readAttribute('value');
            var tr = el.up('tr');
            tr.className = "";
            tr.addClassName('star_' + attr);
        });
    });
});

ReviewStars.scss

#product-review-table {
    thead {
      display: none;
      max-height: 0px;
      overflow: hidden;
    }
    tr {
      td {
        position: relative;
        padding: 0px;
        cursor: pointer;
        &:hover {
          background-color: rgba(0, 0, 0, 0.04);
        }
        &::before {
          width: 13px;
          height: 13px;
          display: block;
          background: url(../../images/bkg_rating.gif);
          background-repeat: no-repeat;
          background-position: center top;
          content: "";
          position: absolute;
          top: 11.5px;
          left: 11.5px;
        }
        input[type="radio"]{
          opacity: 0;
          margin: 0px;
          width: 36px;
          height: 36px;
          cursor: pointer;
        }
      }
      &.star_1 {
        td:nth-of-type(1)::before {
          background-position: center bottom;
        }
      }
      &.star_2 {
        td:nth-of-type(-n+2)::before {
          background-position: center bottom;
        }
      }
      &.star_3 {
        td:nth-of-type(-n+3)::before {
          background-position: center bottom;
        }
      }
      &.star_4 {
        td:nth-of-type(-n+4)::before {
          background-position: center bottom;
        }
      }
      &.star_5 {
        td:nth-of-type(-n+5)::before {
          background-position: center bottom;
        }
      }
    }
  }