getting value of select when onclick

 <select style="color:#9E9E9E; border-radius:5px !important;" name="sex" id="sex">
               <option value="0" disabled="disabled" selected="selected">Select Sex----</option>
               <option style="color:#000" value="1">Male</option>
               <option style="color:#000" value="2">Female</option>
   </select>
  <a href="javascript:" onclick="next()" ><button class="button1">Create Account&Couninue</button></a>
  <div id="sex1" style="display:none" class="invalid">invalid entry for confirm sex</div>
<script>
    function next(){
        var obj = document.getElementById("sex").options;
        var sval = obj[obj.selectedIndex].value;
        if(sval == 0){
            $("#sex1").css('display', 'block');
            return false;
        }else{$("#sex1").css('display', 'none'); }
    }
</script>