[Deff]

<script type="text/javascript">
str1='panama' 
str2='amapan'

function TstСircular_movement(S1,S2) {
 var lenS1=S1.length,lenS2=S2.length;
 if(lenS1==lenS2){
   var s1=S1.split('');
   for(i in s1){
     alert(s1.join(''))
     if(S2==s1.join(''))return i; 
     s1.unshift(s1.pop())
   }
 }
 return -1;
} alert(TstСircular_movement(str1,str2)) //Возвращаем сдвиг или -1
</script>