Disable a div on selecting an option from a drop down menu in HTML

1. make simple dropdown menu
<select id="selelctme">
<option>AABC</option>
<option>BDIV</option>
<option>CDFG</option>
</select>

2. add script
<script>
 $(document).ready(function(){
 $('#selectme').change(function(){
 if($(this:selected).val()=='BDIV')
{
 $('.BDIV').attr('disabled','true');
}
else
{
}

});

});

</script>

in  above simplly use change function this also can be add using javascript onchange function.