Can we use scriptlets inside Javascript?
Question
Here is my Code:
<%@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?
2 answers
solution1
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. Scriptlets can only be included in a JSP page (typically configured to be *.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.
So, to use this tag you would need to manually write a value to the request output stream. To get the desired functionality you need to do the following:
make sure your code is in a JSP page, if yes then
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. For most cases, your should be using JSTL expressions and custom tags.
solution2
1 2015-07-31 14:30:06
you can also use this:
<%@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>
solution3
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.
var x='<%= request.getParameter("ServerName"); %>';
^ output!
… and unless you take measures to escape that data, you render yourself vulnerable to XSS attacks.
(And, obviously, this won't work until the form is actually submitted)
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