jsp - Set array values in javascript from JSTL code - Stack Overflow

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I have a code that looks like this:

In AnalyzeUserClient.jsp:

<c:set var="arrayList"><%= (ArrayList<String>)request.getSession().getAttribute("arrayList") %></c:set>
var sessionId = [];
<c:forEach items=${arrayList} var="id">
sessionId.push("${id}"); // add them one at a time, assuming string values
</c:forEach>

However,this line:

    sessionId.push("${id}");

does not seem to be passing the values into the array "sessionId" (I viewed the source code on browser).So the question is,what can I do to pass the values into the array?

EDIT:I just realised that there are some problems as JSTL is server-side and JavaScript is client-side.So is there a workaround on it?

I have a code that looks like this:

In AnalyzeUserClient.jsp:

<c:set var="arrayList"><%= (ArrayList<String>)request.getSession().getAttribute("arrayList") %></c:set>
var sessionId = [];
<c:forEach items=${arrayList} var="id">
sessionId.push("${id}"); // add them one at a time, assuming string values
</c:forEach>

However,this line:

    sessionId.push("${id}");

does not seem to be passing the values into the array "sessionId" (I viewed the source code on browser).So the question is,what can I do to pass the values into the array?

EDIT:I just realised that there are some problems as JSTL is server-side and JavaScript is client-side.So is there a workaround on it?

• javascript
• jsp
• jstl

Share Improve this question Follow edited Nov 2, 2012 at 6:27 Marcus Dryice Koh asked Nov 2, 2012 at 6:18 Marcus Dryice KohMarcus Dryice Koh 11711 gold badge22 silver badges1313 bronze badges 2

• Regarding your edit about server-side working together with client-side, if the intention is to produce JS that populates the sessionId array and then use it only on the client-side then that doesn't matter. (It only bees a problem if your server-side code tries to use the array too.) You should be able to use server-side code to output JS that populates an array - though I'd consider structuring it in a way that puts the values directly in the array literal [] rather than using .push(). – nnnnnn Commented Nov 2, 2012 at 6:36
• I tried doing: "sessionId["${id}"];" as well,but it is still not working.Is there another way to resolve this? – Marcus Dryice Koh Commented Nov 2, 2012 at 6:41

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1 Answer 1

Sorted by: Reset to default 8

Don't mix EL and scriptlets. In fact, forget about scriptlets pletely:

var sessionId = [];
<c:forEach items="${sessionScope.arrayList}" var="id">
    sessionId.push("${id}"); 
</c:forEach>

Note though that this will generate invalid JavaScript if one of the IDs happens to contain a double quote. So you'd better JavaScript-escape the IDs before, in your controller. And I would suggest a pletely different approach: serialize the list of IDs to a JSON string in your controller, and store this JSON string in request attribute. The JSP page will just need

var sessionId = ${jsonEncodedSessionIds};

which will translate to the following generated code:

var sessionId = ["id1", "id2"];

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