js变量传到jsp表达式

<!-- HTML表单 -->
<form id="myForm" action="process.jsp" method="post">
    <input type="hidden" id="myInput" name="myInput">
</form>

<script>
    // JavaScript变量
    var myVar = "Hello, JSP!";
    
    // 设置表单字段的值
    document.getElementById('myInput').value = myVar;
    
    // 提交表单
    document.getElementById('myForm').submit();
</script>

<!-- process.jsp -->
<%
    String myVar = request.getParameter("myInput");
    out.println("Received from JS: " + myVar);
%>

<!-- HTML -->
<div id="result"></div>

<script>
    // JavaScript变量
    var myVar = "Hello, JSP!";
    
    // AJAX请求
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "process.jsp", true);
    xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    xhr.onreadystatechange = function() {
        if (xhr.readyState === 4 && xhr.status === 200) {
            document.getElementById('result').innerHTML = xhr.responseText;
        }
    };
    xhr.send("myInput=" + encodeURIComponent(myVar));
</script>

<!-- process.jsp -->
<%
    String myVar = request.getParameter("myInput");
    out.println("Received from JS: " + myVar);
%>