1. React react is building a user interface. and this is a javascript library. it's not a framework. the framework is a complete solution but the library is not a complete solution. after that library is best because when what you want and then that item is implemented in the library. 2. React JSX JSX…

1. javaScript data type the javascript data type is two types. primitive value and object and function. primitive types are 9 separate. number, string, boolean, object, function, etc. some are rarely used. the null and undefined value is lonely. and every time you can find out every number, string boolean or etc. uses by…

String : 1. String.prototype.charAt() charAt() return new string. and this default value is the index(0). The first index position is 0, you will know string position then you will call charAt() method. and pass the index number. The first string position of 0, the second is index 1, the third string is index 2…