字符串 —【替换指定项】

var re = /apples/gi;
// 正则表达式表示全局忽略的大小写的目标项

var str = "Apples are round, and apples are juicy.";
var newstr = str.replace(re, "oranges");

把字符串中所有的apples全部替换为oranges并赋予新字符串

console.log(newstr);
// 结果为:oranges are round, and oranges are juicy.