# 字符串常用的方法 ## 1.1 length //獲取字符串的長度 ~~~ var a = "hello world"; alert(a.length) //11 ~~~ ## 增加1.2 ~~~ concat() 方法用于連接兩個或多個字符串。 var a = "hello world"; var b = "good"; var c = a.concat(b); console.log(c); ~~~ ## 查詢1.3 ~~~ charAt(index) //獲取在指定下標的字符 var a = "hello world"; alert(a.charAt(0)) // ~~~ ## 1.4 ~~~ indexOf(value) 檢索字符串出現的位置 var a = "hello world"; var b = a.indexOf(“h”); //0; var c = a.indexOf(“a”); //-1如果沒有返回-1 ~~~ ## 1.5 ~~~ stringObject.slice(start,end) var a = "hello world"; var b = a.slice(0,2); console.log(b); //”he” ~~~ ## 1.6 ~~~ stringObject.substr(start,length) var a = "hello world"; var b = a.substr(0,5); console.log(b); //hello ~~~ ## 1.7 ~~~ stringObject.substring(start,stop) var a = "hello world"; var b = a.substring(0,2); console.log(b); //”he” ~~~ ## 1.8 ~~~ split() 方法用于把一個字符串分割成字符串數組。 stringObject.split(separator,howmany) var a = "hello world"; var b = a.split(""); console.log(b); ~~~ ## 1.9 str.search() //返回下標 ~~~ var a = "hello world"; console.log(a.search("h")); ~~~ ## 1.10 match()返回數組 ~~~ var a ="hello"; console.log(a.match("l")); ~~~ ## 1.11 replace()替換 ~~~ var a ="hello"; var b = a.replace("l","*"); console.log(b); ~~~