// JavaScript Document

function trimAll(sString)
{
   while (sString.substring(0,1) == ' ')
   {
      sString = sString.substring(1, sString.length);
   }
   while (sString.substring(sString.length-1, sString.length) == ' ')
   {
      sString = sString.substring(0,sString.length-1);
   }
   return sString;
}

function comprobarEmail(emilio)
{
   emilio = trimAll(emilio);
   var totalArrobas = 0;
   var totalEspacios =0;  
   for(i=0;i<emilio.length;i++)
   {
      if(emilio.charAt(i) == '@')
      {
         totalArrobas++;
      }
      else if(emilio.charAt(i) == ' ')
      {
         totalEspacios++;
      }  
   }
   return totalArrobas==1 && totalEspacios==0;
}