我们可以在 Javascript 中使用 scriptlet 吗？
[英]Can we use scriptlets inside Javascript?
问题描述
Here is my Code:
这是我的代码：
<%@page contentType="text/html"%>
<%@page pageEncoding="UTF-8"%>
<%@page import="java.sql.*"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Example of Java Server Page with JDBC</title>
</head>
<script>
function myFunction() {
var x='<% request.getParameter("ServerName"); %>';
alert(x);
</script>
<body>
<form>
ServerName: <input type="text" name="ServerName" required> <br><br>
<input type="submit" id="btnSubmit" name="btnSubmit" />
</div>
</form>
</body>
</html>
Here in the above function onclick of a button i want to execute the scriptlets which is inside javascript?在上面的函数 onclick 中，我想执行 javascript 中的 scriptlets？
2 个解决方案
解决方案1
1 2015-07-31 05:13:59
It sounds like you are placing the JSP code within a JavaScript page, or at least in a non-JSP page. 听起来您是将JSP代码放在JavaScript页面中，或者至少是在非JSP页面中。 Scriptlets can only be included in a JSP page (typically configured to be *.jsp). 脚本只能包含在JSP页面中（通常配置为* .jsp）。
The statement as presented, if processed by the JSP compiler, would result in myVar being equal to '' as the scriptlet format you are using <% ... %> executes Java code between the tags, but does not return a result. 所提供的语句如果由JSP编译器处理，将导致myVar等于”，因为您正在使用的<％...％>的scriptlet格式在标记之间执行Java代码，但不会返回结果。
So, to use this tag you would need to manually write a value to the request output stream. 因此，要使用此标记，您需要手动将一个值写入请求输出流。 To get the desired functionality you need to do the following: 要获得所需的功能，您需要执行以下操作：
make sure your code is in a JSP page, if yes then 确保您的代码在JSP页面中，如果是，则
function myFunction() {
var x= '<%= request.getContextPath() %>'; //(note the equals sign)
alert(x);
}
With all that said, scriptlets are viewed as bad practice in most cases. 综上所述，在大多数情况下，scriptlet被视为不良做法。 For most cases, your should be using JSTL expressions and custom tags. 在大多数情况下，您应该使用JSTL表达式和自定义标签。
解决方案2
1 2015-07-31 14:30:06
you can also use this: 您还可以使用以下命令：
<%@page contentType="text/html"%>
<%@page pageEncoding="UTF-8"%>
<%@page import="java.sql.*"%>
<%
String ServerName = (String)request.getParameter("ServerName");
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Example of Java Server Page with JDBC</title>
</head>
<script>
function myFunction() {
var x='<%=ServerName%>';
alert(x);
</script>
<body>
ServerName: <input type="text" name="ServerName" required> <br><br>
<input type="submit" id="btnSubmit" name="btnSubmit" />
</div>
</form>
</body>
</html>
解决方案3
1 2015-07-31 14:35:39
You can, but if you want the result to be passed to the JavaScript you have to output something. 可以，但是如果要将结果传递到JavaScript，则必须输出一些内容。
var x='<%= request.getParameter("ServerName"); %>';
^ output!
… and unless you take measures to escape that data, you render yourself vulnerable to XSS attacks. …除非采取措施逃避该数据，否则您将很容易受到XSS攻击。
(And, obviously, this won't work until the form is actually submitted) （而且，显然，这要等到实际提交表单后才能生效）
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