JAVACSCRIPT追記-バイアス関数を使用してオブジェクトタイプを判断

//        
var isType = function(type){
  return function(obj){
    return toString.call(obj)=='[object '+type+']';
  }
};
//     
var isArray= isType('Array');
var isBoolean = isType('Boolean');
var isFunction = isType('Function');
var isNumber = isType('Number');

//     
var isArray_ = isArray(['a','d']);
var isBoolean_ = isBoolean(true);
var isFunction_ = isFunction(isType);
var isNumber_ = isNumber(888);

alert("['a','d'] is an Array?"+isArray_);
alert("true is a Boolean? "+isBoolean_);
alert('isType is a Function?'+isFunction_);
alert('888 is a Number?'+isNumber_);

参考:バイアス関数の使用