[Vlasenko Fedor]

<style>
      div.a {
        padding:5px;
        margin: 5px;
        background-color: red;
        float: left;
      }
    </style>
    <div class="a">1</div>
    <div class="a">2</div>
    <div class="a">3</div>
    <div class="a">4</div>
    <div class="a">5</div>
    <script>
      (function () {
        var divs = document.querySelectorAll("div.a"),
          len = divs.length,
          i = 0;
        for (; divs[i].setAttribute("onclick", "clval(" + i + ")"), ++i < len;);
        clval = function (e) {
          alert(e);
        };
      }());
    </script>