常用API——字符串String型函数

上图：

声明

var myString = new String("Every good boy does fine.");

var myString = "Every good boy does fine.";

字符串连接

var myString = "Every " + "good boy " + "does fine.";

var myString = "Every "; myString += "good boy does fine.";

截取字符串

//截取第 6 位开始的字符

var myString = "Every good boy does fine.";

var section = 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

var myString = "Every good boy does fine.";

var section = 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

var myString = "Every good boy does fine.";

var section = myString.slice(11,-6); //结果: "boy does"

//从第 6 位开始截取长度为 4 的字符

var myString = "Every good boy does fine.";

var section = myString.substr(6,4); //结果: "good"

转换大小写

var myString = "Hello";

var lcString = myString.toLowerCase(); //结果: "hello"

var ucString = myString.toUpperCase(); //结果: "HELLO"

字符串比较

var aString = "Hello!";

var bString = new String("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)

检索字符串

var myString = "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

查找替换字符串

var myString = "I is your father.";

var result = myString.replace("is","am"); //结果: "I am your father."

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

将字符转换成Unicode编码

var myString = "hello";

var code = myString.charCodeAt(3); //返回"l"的Unicode编码(整型)

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

将字符串转换成URL编码

var myString = "hello all";

var code = encodeURI(myString); //结果: "hello%20all"

var str = decodeURI(code); //结果: "hello all"

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