window.onload=function(){
populatedropdown("yeardropdown5back")
populatedropdown("yeardropdown5back2")
populatedropdown("yeardropdown5back3")
}

function populatedropdown(yearfield){
var today=new Date()
var yearfield=document.getElementById(yearfield)

var thisyearneg5=today.getFullYear()
var thisyear=thisyearneg5-5;
for (var y=1; y<6; y++){
yearfield.options[y]=new Option(thisyear, thisyear)
thisyear+=1
}
yearfield.options[0]=new Option(today.getFullYear(), today.getFullYear(), true, true) //select today's year
}