JavaScript字符串操作

var a = "hello";
var b = ",world";
var c = a.concat(b);
alert(c);
//c = "hello,world"

var index1 = a.indexOf("l");
//index1 = 2
var index2 = a.indexOf("l",3);
//index2 = 3

var get_char = a.charAt(0);
//get_char = "h"

var index1 = lastIndexOf('l');
//index1 = 3
var index2 = lastIndexOf('l',2)
//index2 = 2

var re = new RegExp(/^/w+$/);
var is_alpha1 = a.match(re);
//is_alpha1 = "hello"
var is_alpha2 = b.match(re);
//is_alpha2 = null

var sub_string1 = a.substring(1);
//sub_string1 = "ello"
var sub_string2 = a.substring(1,4);
//sub_string2 = "ell"

var sub_string1 = a.substr(1);
//sub_string1 = "ello"
var sub_string2 = a.substr(1,4);
//sub_string2 = "ello"

var result1 = a.replace(re,"Hello");
//result1 = "Hello"
var result2 = b.replace(re,"Hello");
//result2 = ",world"

var index1 = a.search(re);
//index1 = 0
var index2 = b.search(re);
//index2 = -1

var sub_string1 = a.slice(1);
//sub_string1 = "ello"
var sub_string2 = a.slice(1,4);
//sub_string2 = "ell"

var arr1 = a.split("");
//arr1 = [h,e,l,l,o]

var len = a.length();
//len = 5

var lower_string = a.toLowerCase();
//lower_string = "hello"

var upper_string = a.toUpperCase();
//upper_string = "HELLO"