d3_events1.html

<!doctype html>
<html>
<head>
    <style>
        div {
            height: 100px;
            width: 100px;
            background-color: steelblue;
            margin:5px;
        }
    </style>
    <script src="d3.js"></script>
</head>
<body>
<div> </div>
<div></div>
<script>
    var index = 0;
    testme = function(){ console.log("I was invoked "+ index++);};

    d3.selectAll("div")
      .on("click",testme)

      .on("mouseover", function(){
          d3.select(this)
            .style("background-color", "orange")})

      .on("mouseout", function(){ d3.select(this).style("background-color", "steelblue")})
</script>
</body>
</html>