** 1。typeof **
console.log( typeof(1) );//number
console.log( typeof "abc" );//string
console.log(typeof false); //boolean
console.log(typeof function () {
}); //function
console.log(typeof {
}); //object
console.log(typeof undefined); //undefined
//typeof无法判断出数组、对象、null的具体类型,
2.インスタンスの
console.log( [1,2,3] instanceof Array);//true
console.log( {
"name":"a"} instanceof Array );//false
console.log( "abcde" instanceof String );//false
****
3.Object.prototype.toString.call
****
console.log( Object.prototype.toString.call( "234" ) );//string
console.log( Object.prototype.toString.call( null ) );//null
console.log( Object.prototype.toString.call( [1] ) );//Array
4.パッケージ関数はデータタイプを検出します。
function checkType( date){
var type=Object.prototype.toString.call(date);
type= type.substr( 8,type.length-9 );
return type;
};
var x=checkType(1);
console.log(x);//number