gistfile1.js

function funcName(){
   var varname = 0;
   if(condition){
      var varname = 1;
   }
}

//will be interpreted as

function funcName(){
   var varname;
   varname = 0;
   if(condition){
      varname = 1;
   }
}

//and therefore is the same as 

function funcName(){
   var varname = 0;
   if(condition){
      varname = 1;
   }
}