JSP javascript escape with JSTL

jsp-javascript-escape-sample.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>

<%-- setup --%>
<% pageContext.setAttribute("carriageReturn", "\r"); %> 
<% pageContext.setAttribute("newLine", "\n"); %> 
<c:set var="singleQuotes">'</c:set>
<c:set var="singleQuotesReplace">\'</c:set>
<c:set var="doubleQuotes">"</c:set>
<c:set var="doubleQuotesReplace">\"</c:set>
<c:set var="backslash">\</c:set>
<c:set var="backslashReplace">\\</c:set>

<%-- your string --%>
<c:set var="STRING_TO_ESCAPE">This is only a littl' test, "escape me"!</c:set>
<c:set var="ESCAPED_STRING" value="${
  fn:replace(
    fn:replace(
      fn:replace(
        fn:replace(
          fn:replace(STRING_TO_ESCAPE, backslash, backslashReplace),
        carriageReturn, ' '),
      newLine, ' '), 
    singleQuotes, singleQuotesReplace),
  doubleQuotes, doubleQuotesReplace)
}" />

<%-- output --%>
Escaped String: <c:out value="${ESCAPED_STRING}" escapeXml="false" />

I think you could also insert the following replace as the inner-most replace call (or in any case before the replaceSingleQuotes and replaceDoubleQuotes):

fn:replace(STRING_TO_ESCAPE,backslash,backslashReplace)

where, of course,
<c:set var="backslash">&lt;/c:set>
<c:set var="backslashReplaceReplace">\</c:set>

@sorin-postelnicu yeah you're right! also the backslashes need to be replaced. Good one! ;)