Java/JS/JSTL - how to get property from javabean/display error message [duplicate]

This question already has answers here: Access Java / Servlet / JSP / JSTL / EL variables in JavaScript (5 answers) Closed 7 years ago.

In my html, I need a开发者_JS百科 property from my bean and store it in a variable - how can I do this?

What I'm trying to do is, display an error message when a user's login fail - I know I can do this with javascript, but I don't know how I can "call" this javascript to load when a login is unsuccessful.

Many ways to do this.. but I don't know how to do any of them.

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Like HTML and CSS, JS is part of template text. Just let JSP print it as if it is a JS variable.

<script>var foo = '${bean.foo}';</script>

You just need to make sure that the generated HTML looks the way so that JS understands it.

<script>var foo = 'bar';</script>

With JSP/JSTL/EL you can control the output whatever way you want. You can use JSTL <c:if> to print it conditionally. You can use EL conditional operator ${condition ? printIfTrue : printIfFalse } to toggle output based on a condition. Etcetera.

See also:

• Communication between Java/JSP/JSF and JavaScript

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You can use @BalusC's way, but if you don't want to place <script> tag in your JSP code, one option is to set the value as a hidden field:-

<input id="foo" type="hidden" value="${bean.foo}" />

Then, in your javascript, do this:-

var foo = document.getElementById("foo").value;