jsp取js变量值

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

<script>
    var myVar = "Hello, JSP!";
    document.getElementById('hiddenField').value = myVar;
    document.getElementById('myForm').submit();
</script>

<!-- process.jsp -->
<%
    String value = request.getParameter("hiddenField");
    out.println("Received value: " + value);
%>

<!-- HTML & JavaScript -->
<script>
    var myVar = "Hello, JSP!";
    fetch('process.jsp', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/x-www-form-urlencoded',
        },
        body: 'myVar=' + encodeURIComponent(myVar)
    })
    .then(response => response.text())
    .then(data => console.log(data));
</script>

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

<!-- HTML & JavaScript -->
<script>
    var myVar = "Hello, JSP!";
    window.location.href = "process.jsp?myVar=" + encodeURIComponent(myVar);
</script>

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