function contains(masterString, subString) {
if(subString.length > masterString.length){
    return false;
}
for(var i=subString.length-1; i<masterString.length; i++){
    if(concatString(i - subString.length-1, i, masterString) === subString){
        return true;
    }
}
  return false;

}

function concatString(index1, index2, string){
    var conString = '';
  console.log(index1, index2-1, string);
    for(var i=index1; i<index2-1; i++){
        conString += string[i];
    }
  console.log(conString);
    return conString;
}


contains('abcd', 'bc');