Js difference in the instanceof and typeof
Demo 1
var v5=new Number("22");
document.write(typeof v5+"<br/>"); //---->object
document.write( v5 instanceof Number ); //---->true
document.write("<br/>"+v5);
result:
Tour 2:
// test string aa is not of type String
//document.write(typeof "aa" +"<br/>"); //---->string
// An example of test string aa is not a String
//document.write("aa" instanceof String); //---->false
// If you create an instance of a new way of it, then go to test two of the above
var str3=new String("bbb");
document.write(typeof str3 +"<br/>"); //---->Object
// An example of test string aa is not a String
document.write(str3 instanceof String); //---->true
Demonstration Results
Tour 3:
// test string aa is not of type String
document.write(typeof "aa" +"<br/>"); //---->string
// An example of test string aa is not a String
document.write("aa" instanceof String); //---->false
// If you create an instance of a new way of it, then go to test two of the above
var str3=new String("bbb");
//document.write(typeof str3 +"<br/>"); //---->Object
// An example of test string aa is not a String
//document.write(str3 instanceof String); //---->true
result
Demo 4
document.write(typeof 1 +"<br/>"); //--->number
document.write(1 instanceof Number ); //---->false
/* var v5=new Number("22");
document.write(typeof v5+"<br/>"); //---->object
document.write( v5 instanceof Number ); //---->true
document.write("<br/>"+v5); */
Summary: As can be seen from the above three demo for immediate thought is a certain type of variable, such as plastic surgery is considered 1, "aa" is String If typeof keywords get is in line with our ideas
如1 typeof Number--àtrue
But if 1 instanceof Numberàfalse
But if they go to a new object, then, then go call these two methods, see below
var str3=new String("bbb");
//document.write(typeof str3 +"<br/>"); //---->Object
// An example of test string aa is not a String
//document.write(str3 instanceof String); //---->true
or
var v5=new Number("22");
document.write(typeof v5+"<br/>"); //---->object
document.write( v5 instanceof Number ); //---->true
That is out of our new and if we are not that type of time with new typeof get is of type Object, but instanceof that is to verify compliance with our ideas