请教一个单引双引的问题

Question

<script>
function f1()
{
self.location.href="countryEntry.jsp?countrycode='nnn'"    
}
</script>
<input type="submit" name="Submit32" value="View" onClick='f1()' 
ID=Submit1>

Answer 1

<input type="submit" name="Submit32" value="View" onClick="self.location.href='countryEntry.jsp?countrycode=' + nnn">

Answer 2

var nnn = "xxx";
var url = "self.location.href='countryEntry.jsp?countrycode="+nnn;
onClick=url

Answer 3

应该是：
function link(){
   var nnn = "xxx";
   var url = "self.location.href='countryEntry.jsp?countrycode="+nnn;
}
onClick="link();"