写一段代码,吧jap页面中的参数传递到js中并在js中通过ajax请求后端接口

Sure, here's an example code snippet that passes parameters from a JSP page to JavaScript and makes an AJAX request to a backend API:

<!-- define a variable to hold the value of the parameter -->
<%
  String parameterValue = request.getParameter("parameterName");
%>

<!-- pass the parameter value to a JavaScript variable -->
<script>
  var parameterValue = '<%= parameterValue %>';
</script>

<!-- make an AJAX request to the backend API using jQuery -->
<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
<script>
  $.ajax({
    url: "/api/endpoint",
    type: "POST",
    data: JSON.stringify({parameter: parameterValue}),
    contentType: "application/json",
    success: function(data) {
      console.log(data);
    },
    error: function(error) {
      console.log(error);
    }
  });
</script>

Note that this code assumes you're using jQuery for the AJAX request, and that the backend API is expecting a JSON object with a property named "parameter". You'll need to modify it to fit your specific use case.