get automatic value

Question

how to get data-prefix value of drop down selected value in next textbox using javascript.

 my code is below:

 

<div class="form-group">
<div class="prefix-inner">
<div class="form-group">
<select class="form-control countryData countrySelect" required="" disabled="" >

<option data-prefix="91" selected="selected" value="IN">India</option>

<option data-prefix="62" value="ID">Indonesia</option> 

</select>
</div>
<div class="form-group row">
<div class="col-xs-4">
<input type="text" class="form-control PhonePrefix text-center prefixCountrySel" placeholder="+000" disabled="" >
</div> 

 

 

selected value is india is data-prefix code is 91 is automatically display in below textbox using javascript