Javascript Form How to - Get select drop down value length

Question

We would like to know how to get select drop down value length.

Answer


<html>
<head>
    <script language="JavaScript">
    function openWin(){<!--from  w  w w  .j a v  a 2s .  com-->
      var myInstance = document.myForm.mySelect;

      console.log("The length is: " + myInstance.length + "<br>");
    }
    </script>
    </head>
<body>
    <form name="myForm">My Favorite Sport is:
      <select name="mySelect">
        <option value=A>AA</option>
        <option value=B>BB</option>
        <option value=C>CC</option>
        <option value=D>DD</option>
      </select>
    <input type=BUTTON value="Click to Process" name="myButton"
             onClick="openWin()">
    </form>
</body>
</html>

The code above is rendered as follows: