一、string中的常用属性

 

 1. length

说明：

　　字符串的长度属性，一直保持跟踪着该字符串中包含的字符数。

 

 

 二、string中的常用方法

 

 1. toLowerCase() 和 toUpperCase()

说明：

　　toLowerCase(): returns a copy of the string with its letters converted to lowercase. Numbers, symbols, and other characters are not affected.

　　toUpperCase(): returns a copy of the string with its letters converted to capitals. Numbers, symbols, and other characters are not affected.

 

 2. trim()

说明：

　　returns a copy of the string with beginning and ending whitespace characters removed.