<!DOCTYPE html>
<html>
<head>
    <title>每隔第几个替换</title>
    <script>
        function replaceNth() {
            var inputText = document.getElementById("inputText").value; // 获取输入的文本
            var searchText = document.getElementById("searchText").value; // 获取要替换的内容
            var replaceText = document.getElementById("replaceText").value; // 获取替换后的内容
            var n = parseInt(document.getElementById("nthText").value); // 获取每隔第几个

            var count = 0;
            var replacedText = inputText.replace(new RegExp(searchText, "g"), function(match) {
                count++;
                if (count % n === 0) {
                    return replaceText;
                } else {
                    return match;
                }
            });

            document.getElementById("outputText").textContent = replacedText; // 显示替换后的文本
        }
    </script>
</head>
<body>
    <label for="inputText">输入文本：</label>
    <textarea id="inputText" rows="5" cols="50"></textarea>
    <br>
    <label for="searchText">要替换的内容：</label>
    <input type="text" id="searchText">
    <br>
    <label for="replaceText">替换后的内容：</label>
    <input type="text" id="replaceText">
    <br>
    <label for="nthText">每隔第几个：</label>
    <input type="number" id="nthText">
    <br>
    <button onclick="replaceNth()">替换</button>
    <br>
    <label for="outputText">替换结果：</label>
    <textarea id="outputText" rows="5" cols="50" readonly></textarea>
</body>
</html>