Required Attribute not Working in Select Option

"required" attribute in select option not working?

Problem File:

<select name="category" required="required" class="form-control"> 

 <option value=" ">--Select Category--</option> 

 <option value="Chocklet">Chocklet</option> 

</select>

Solution File: Try to remove space value in your select category option

<select name="category" required="required" class="form-control"> 

 <option value="">--Select Category--</option> //Here was the problem

 <option value="asd">asd</option> 

</select>