js判断数据类型

function isArray(obj){
    return (typeof obj=='object')&&obj.constructor==Array;
}

function isString(str){
    return (typeof str=='string')&&str.constructor==String;
}

function isNumber(obj){
    return (typeof obj=='number')&&obj.constructor==Number;
}

function isDate(obj){
    return (typeof obj=='object')&&obj.constructor==Date;
}

function isFunction(obj){
    return (typeof obj=='function')&&obj.constructor==Function;
}

function isObject(obj){
    return (typeof obj=='object')&&obj.constructor==Object;
}