js .replace()

str.replace(searchValue, replaceValue);

let str = "Hello, world!";
let newStr = str.replace("world", "JavaScript");
console.log(newStr); // 输出: "Hello, JavaScript!"

let str = "The quick brown fox jumps over the lazy dog.";
let newStr = str.replace(/the/gi, "a");
console.log(newStr); // 输出: "The quick brown fox jumps over a lazy dog."

let str = "apple, apple, apple";
let newStr = str.replace(/apple/g, "orange");
console.log(newStr); // 输出: "orange, orange, orange"

let str = "1, 2, 3, 4, 5";
let newStr = str.replace(/\d+/g, function(match) {
    return parseInt(match) * 2;
});
console.log(newStr); // 输出: "2, 4, 6, 8, 10"

let str = "Hello, world!";
let newStr = str.replace("world", "JavaScript");
console.log(str); // 输出: "Hello, world!" (原始字符串未变)