request.getAttribute in javascript shows null

Question

I am executing a query in jsp and using resultSet.getString() to get that field.

String eKnowledge = resultset.getString("knowledge");

Then using request.setAttribute() to set that field in jsp.

request.setAttribute("actualKnowledge", eKnowledge);

I am using request.getAttribute() in javascript to get that object.

<script type="text/javascript"> 

    function moreInformationDisplay() {
        var jsKnowledge = <%=request.getAttribute("actualKnowledge")%>;
        alert(jsKnowledge); 
    }

</script>

But the alert message shows null. Can someone please help me with this problem.

`<%=request.getAttribute("actualKnowledge")%>` - this is pre-processed on the server side before the page is loaded into the browser - are you hoping for some magic two way communication between server and client without using AJAX? — Jaromanda X, Mar 16 '17 at 23:27

score 0 · Answer 1 · edited May 23 '17 at 12:25

0

If your javaScript block is inserted in a valid JSP page, after the call to .setAttribute and resultset.getString("knowledge") is not null, then your code should work fine.

However this is bad practice and should be avoided. You should be using JSTL How to avoid Java code in JSP files?

Your code could also be vunerable to XSS injection, if eKnowledge contains user input. It would be a good idea to escape it with a tool like OWASP Java encoder

edited May 23 '17 at 12:25

Community

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1

answered Mar 16 '17 at 23:38

Mathieu St-Louis

41
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javaScript block is inside the same JSP page. – Dhruv Kadia Mar 16 '17 at 23:42
Can you output <%= eKnowledge %> in your jsp and see what it outputs, when rendred to HTML? – Mathieu St-Louis Mar 16 '17 at 23:50
eKnowledge prints the value which is stored in database. – Dhruv Kadia Mar 16 '17 at 23:59
Try to add some quotes before and after the expression:var jsKnowledge = "<%=request.getAttribute("actualKnowledge")%>"; – Mathieu St-Louis Mar 17 '17 at 00:03
Tried that.. no success – Dhruv Kadia Mar 17 '17 at 00:13

request.getAttribute in javascript shows null

1 Answers1