是否可以根据窗口变量在 JSP 中有条件地加载脚本标签？

Question

Hi I have to conditionally load a script in one of my jsp files based on a window variable. Can someone suggest me how can i acheive this. Is it possible ?

Current behaviour : 1. mytest.jsp file 2. currently loading as

I wanted to acheive something like

<c:if **test="${window.loadScripts}**"> 
 <script type="text/javascript" src="myscript.js"></script>
 <script type="text/javascript" src="myscript2.js"></script>

</c:if>

Answer 1

You need to send the client browser data to the server. On a "true" response the browser will load the additional scripts.

This is the code for the backend service: getjsvariables.jsp

 <%@page contentType="text/html" pageEncoding="UTF-8"%> <% request.setCharacterEncoding("UTF-8");%> <jsp:scriptlet> String test = request.getParameter("test"); if(test.equals("x")) { out.print("doprint"); } else { out.print("dontprint"); } </jsp:scriptlet>

This will be your code for the ajax call: getvariables.js

 function postData(url, data, success) { // convert post data to string let i = 0; let post_data = ""; for (const [key, value] of Object.entries(data)) { if (i > 0) { result += "&"; } post_data += key + "=" + value; i++; } // ajax call let xhttp = new XMLHttpRequest(); xhttp.onreadystatechange = function () { if (this.readyState == 4 && this.status == 200) { success(this.responseText); } }; xhttp.open("POST", url, true); xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); xhttp.send(postData(postData)); } let printYourScripts = function (response) { if(response == "doprint") { let html = '<script src="script1.js"></script>'; html += '<script src="script2.js"></script>'; document.body.innerHTML += html; } } let postData = { test: "x" }; // RUN let url = "getjsvariables.jsp"; postData(url, postData, printYoutScripts);