1. What are the basic data types of JS

Basic types Number, String, Boolean, Null, Undefined reference type Object

2. What types are returned by typefo in js

number, string, boolean, undefined, function, object

3. What is the difference between return, break, and continue

A return must be written inside the function. If a return is encountered, the rest of the code inside the function is not executed. You can also return a value for external use. Break breaks the loop and the rest of the loop is not executed. Continue This cycle, the rest of the cycle continues.

4. What is the difference between typeof and instance of

Typeof determines the typeof the object, and there are six possibilities for the return value. Number, string, Boolean, undefined, function, object instance of checks whether the object is an instance of the other object. The return value is true or false

5. What’s the difference between == and ==

== Determine whether the values on the left and right sides are consistent, but only the value, not the type. === determines both value and type.

6. How about casts and implicit conversions of JS

ParseInt, parseFloat, and Number are cast. -=, /=, %=, =, are implicit conversions

7. What is the difference between a GET request and a POST request

In a GET request, parameters are stored in the URL, while in a POST request, parameters are stored in the request body. Theoretically, POST is more secure because the URL length cannot exceed 1KB. However, IN a GET request, parameters are stored in the URL.