How to set the JSTL variable value in javascript?

Question

How to set the JSTL variable value in java script?

<script>

 function function1()

 { 

  var val1 = document.getElementById('userName').value;

  <c:set var="user" value=""/>  // how do i set val1 here?   

 }
 </script>

How do I set the 'user' variable (JSTL) value from 'val1' (Java script)?

Answer 1

You have to use the normal string concatenation but you have to make sure the value is a Valid XML string, you will find a good practice to write XML in this source http://oreilly.com/pub/h/2127, or if you like you can use an API in javascript to write XML as helma for example.

Answer 2

It is not possible because they are executed in different environments (JSP at server side, JavaScript at client side). So they are not executed in the sequence you see in your code.

var val1 = document.getElementById('userName').value; 

<c:set var="user" value=""/>  // how do i set val1 here? 

Here JSTL code is executed at server side and the server sees the JavaScript/Html codes as simple texts. The generated contents from JSTL code (if any) will be rendered in the resulting HTML along with your other JavaScript/HTML codes. Now the browser renders HTML along with executing the Javascript codes. Now remember there is no JSTL code available for the browser.

Now for example,

<script type="text/javascript">
<c:set var="message" value="Hello"/> 
var message = '<c:out value="${message}"/>';
</script>

Now for the browser, this content is rendered,

<script type="text/javascript">
var message = 'Hello';
</script>

Hope this helps.