JavascriptString object_javascript skills

The javascript database operation methods include string case sensitivity, string SEARCH, string extraction, and other string methods in Javascr platinum pt:
1. Change the string case sensitivity.
String. toUpperCase ();
String. toLowerCase ();
2. string SEARCH
The indexOf () method is used to determine whether a short string is in another long string. If so, the index of the position is returned. If not, the return value is-1.
Usage: long string. indexOf ("short string ")
3. Extract character copies and substrings
The charAt () method can extract a single character from the specified position of the string.
The substring () method can be used to extract a consecutive string. the start and end positions must be provided (Note: The characters at the end position are not included in the extracted substring .)