How to keep dropdown first value as default after refreshing the page using javascript

<input type="hidden" name="selectedValue" value="0"/>  

put the above one in just below of your select tag

and do this in your servlet

String selectedValue = `request.getParameter("selectedValue")` 

now set the selectedValue into the servlet request

create a JS function in your final jsp

function selectedValue(){  

    var value =<%=request.getParameter("selectedValue")%>;  
    if(value !=null)  
        {

        document.f1.slvalue.selectedIndex=value ;          

        }    

} 

call the selectedValue() function on bodyload of your final jsp page. "slvalue" is a name of your select tag
Ref.:How to keep Dropdownlist value same after refresh the page[^]