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<%@page contentType="text/html; charset=UTF-8" %>
<%@ taglib prefix="fn" uri="https://java.sun.com/jsp/jstl/functions" %>
<%@ taglib prefix="my" uri="https://tomcat.apache.org/jsp2-example-taglib"%>
<html>
<head>
<title>JSP 2.0 Expression Language - Functions</title>
</head>
<body>
<h1>JSP 2.0 Expression Language - Functions</h1>
<hr>
An upgrade from the JSTL expression language, the JSP 2.0 EL also
allows for simple function invocation. Functions are defined
by tag libraries and are implemented by a Java programmer as
static methods.
<blockquote>
<u><b>Change Parameter</b></u>
<form action="functions.jsp" method="GET">
foo = <input type="text" name="foo" value="${fn:escapeXml(param["foo"])}">
<input type="submit">
</form>
<br>
<code>
<table border="1">
<thead>
<td><b>EL Expression</b></td>
<td><b>Result</b></td>
</thead>
<tr>
<td>\${param["foo"]}</td>
<td>${fn:escapeXml(param["foo"])} </td>
</tr>
<tr>
<td>\${my:reverse(param["foo"])}</td>
<td>${my:reverse(fn:escapeXml(param["foo"]))} </td>
</tr>
<tr>
<td>\${my:reverse(my:reverse(param["foo"]))}</td>
<td>${my:reverse(my:reverse(fn:escapeXml(param["foo"])))} </td>
</tr>
<tr>
<td>\${my:countVowels(param["foo"])}</td>
<td>${my:countVowels(fn:escapeXml(param["foo"]))} </td>
</tr>
</table>
</code>
</blockquote>
</body>
</html>