常用字符串API

字符串(String)

1.声明

varmyString =newString(“Every good boy does fine.”);

varmyString = “Every good boy does fine.”;

2.字符串连接

varmyString = “Every ” + “good boy ” + “does fine.”;

varmyString = “Every “; myString += “good boy does fine.”;

3.截取字符串

//截取第 6 位开始的字符

varmyString = “Every good boy does fine.”;

varsection = myString.substring(6);//结果: “good boy does fine.”

//截取第 0 位开始至第 10 位为止的字符

varmyString = “Every good boy does fine.”;

varsection = myString.substring(0,10);//结果: “Every good”

//截取从第 11 位到倒数第 6 位为止的字符

varmyString = “Every good boy does fine.”;

varsection = myString.slice(11,-6);//结果: “boy does”

//从第 6 位开始截取长度为 4 的字符

varmyString = “Every good boy does fine.”;

varsection = myString.substr(6,4);//结果: “good”

4.转换大小写

varmyString = “Hello”;

varlcString = myString.toLowerCase();//结果: “hello”

varucString = myString.toUpperCase();//结果: “HELLO”

5.字符串比较

varaString = “Hello!”;

varbString =newString(“Hello!”);

if( aString == “Hello!” ){ }//结果: true

if( aString == bString ){ }//结果: true

if( aString === bString ){ }//结果: false (两个对象不同,尽管它们的值相同)

6.检索字符串

varmyString = “hello everybody.”;

// 如果检索不到会返回-1,检索到的话返回在该串中的起始位置

if( myString.indexOf(“every”) >-1){ }//结果: true

7.查找替换字符串

varmyString = “I is your father.”;

varresult = myString.replace(“is”,”am”);//结果: “I am your father.”

8.特殊字符:

\b : 后退符 \t : 水平制表符

\n : 换行符 \v : 垂直制表符

\f : 分页符 \r : 回车符

\” : 双引号 \’ : 单引号

\\ : 反斜杆

9.将字符转换成Unicode编码

varmyString = “hello”;

varcode = myString.charCodeAt(3);//返回”l”的Unicode编码(整型)

varchar =String.fromCharCode(66);//返回Unicode为66的字符

10.将字符串转换成URL编码

varmyString = “hello all”;

varcode =encodeURI(myString);//结果: “hello%20all”

varstr =decodeURI(code);//结果: “hello all”

//相应的还有: encodeURIComponent() decodeURIComponent()