How to get a index value from foreach loop in jstl

Question

I have a value set in the request object like the following,

String[] categoriesList=null;
categoriesList = engine.getCategoryNamesArray();
request.setAttribute("categoriesList", categoriesList );

and this is how I iterate in jsp page

<% if(request.getAttribute("categoriesList") != null) { %>
<c:forEach var="categoryName" items="${categoriesList}">
   <li><a onclick="getCategoryIndex()" href="#">${categoryName}</a></li>
</c:forEach>
<% }%>

How do I get index of each element and pass it to JavaScript function onclick="getCategoryIndex()".

score 268 · Accepted Answer · edited Jun 04 '14 at 20:55

268

use varStatus to get the index c:forEach varStatus properties

<c:forEach var="categoryName" items="${categoriesList}" varStatus="loop">
    <li><a onclick="getCategoryIndex(${loop.index})" href="#">${categoryName}</a></li>
</c:forEach>

edited Jun 04 '14 at 20:55

Paul Gray

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answered Sep 16 '13 at 10:41

newuser

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I get this `Uncaught ReferenceError: `loop is not defined ` and +1 for your effort – Java Questions Sep 16 '13 at 10:46
onClick of the element displayed – Java Questions Sep 16 '13 at 11:01
Because the varStatus value contains value upto the loop iteration. After that the value is not a valid one. so only you got the exception. For which purpose you need the index – newuser Sep 16 '13 at 11:08
I need to know the index[location] of each element comes in the String Array. – Java Questions Sep 16 '13 at 11:10
it works :) if I do this way onclick="getCategoryIndex(${loop.index})" ...thanks for the help – Java Questions Sep 16 '13 at 11:13
if I want to store this loop value in to a variable and pass the same to javascript method than how do I go about ? – Java Questions Sep 16 '13 at 11:37
I sued this way `` but it always gives me `0` when do this `var categoryIndex = $('#categoryIndex').val();` – Java Questions Sep 16 '13 at 11:41
created new question `http://stackoverflow.com/questions/18827153/jstl-foreach-loop-setting-values-to-a-hidden-variable-returns-zero-always` – Java Questions Sep 16 '13 at 11:50
Sorry now only i saw this – newuser Sep 17 '13 at 01:09
I think the answer is like this: Family member # is
Check [this link](http://www.java2s.com/Tutorial/Java/0380__JSTL/JSTLForEachStatusCount.htm) – Daniel Carpio Contreras Feb 18 '18 at 04:14

score 26 · Answer 2 · edited Jul 19 '21 at 09:30

I faced similar problems. After research I understand we have some more options with the varStatus="loop". It can either use a zero based index or one based index:

The ${loop.index} uses a 0 base index
The ${loop.count} uses a 1 base index

For Example :

<c:forEach var="currentImage" items="${cityBannerImages}" varStatus="loop">
<picture>
   <source srcset="${currentImage}" media="(min-width: 1000px)"></source>
   <source srcset="${cityMobileImages[loop.count]}" media="(min-width:600px)"></source>
   <img srcset="${cityMobileImages[loop.count]}" alt=""></img>
</picture>
</c:forEach>

For more Info please check this link.

Rahul · Answer 3 · 2013-09-17T09:48:35.980

14

You can use the varStatus attribute like this:-

<c:forEach var="categoryName" items="${categoriesList}" varStatus="myIndex">

myIndex.index will give you the index. Here myIndex is a LoopTagStatus object.

Hence, you can send that to your javascript method like this:-

<a onclick="getCategoryIndex(${myIndex.index})" href="#">${categoryName}</a>

edited Sep 17 '13 at 09:48

answered Sep 16 '13 at 10:42

Rahul

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I get this `Uncaught ReferenceError: myIndex is not defined ` and +1 for your effort – Java Questions Sep 16 '13 at 10:46

score 1 · Answer 4 · edited Aug 05 '19 at 20:40

1

This works for me:

<c:forEach var="i" begin="1970" end="2000">
    <option value="${2000-(i-1970)}">${2000-(i-1970)} 
     </option>
</c:forEach>

edited Aug 05 '19 at 20:40

Igor

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answered Aug 05 '19 at 19:17

Pradeep

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score 0 · Answer 5 · edited Jul 18 '19 at 19:17

0

<a onclick="getCategoryIndex(${myIndex.index})" href="#">${categoryName}</a>

above line was giving me an error. So I wrote down in below way which is working fine for me.

<a onclick="getCategoryIndex('<c:out value="${myIndex.index}"/>')" href="#">${categoryName}</a>

Maybe someone else might get same error. Look at this guys!

edited Jul 18 '19 at 19:17

cristid9

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answered Dec 22 '16 at 08:13

Rakesh Kumar

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How to get a index value from foreach loop in jstl

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